Refer to OS X as "macOS", except for the port name which is still "darwin".

We weren't terribly consistent about whether to call Apple's OS "OS X"
or "Mac OS X", and the former is probably confusing to people who aren't
Apple users.  Now that Apple has rebranded it "macOS", follow their lead
to establish a consistent naming pattern.  Also, avoid the use of the
ancient project name "Darwin", except as the port code name which does not
seem desirable to change.  (In short, this patch touches documentation and
comments, but no actual code.)

I didn't touch contrib/start-scripts/osx/, either.  I suspect those are
obsolete and due for a rewrite, anyway.

I dithered about whether to apply this edit to old release notes, but
those were responsible for quite a lot of the inconsistencies, so I ended
up changing them too.  Anyway, Apple's being ahistorical about this,
so why shouldn't we be?

40 files changed, 102 insertions, 99 deletions

diff --git a/config/c-library.m4 b/config/c-library.m4
index 50d068d3fb4..d330b0cf952 100644
--- a/config/c-library.m4
+++ b/config/c-library.m4
@@ -292,8 +292,8 @@ AC_MSG_RESULT([$pgac_cv_snprintf_size_t_support])
 
 # PGAC_TYPE_LOCALE_T
 # ------------------
-# Check for the locale_t type and find the right header file.  Mac OS
-# X needs xlocale.h; standard is locale.h, but glibc also has an
+# Check for the locale_t type and find the right header file.  macOS
+# needs xlocale.h; standard is locale.h, but glibc also has an
 # xlocale.h file that we should not use.
 #
 AC_DEFUN([PGAC_TYPE_LOCALE_T],
diff --git a/configure b/configure
index 5fc8c442a28..55c771a11e9 100755
--- a/configure
+++ b/configure
@@ -7658,9 +7658,9 @@ $as_echo "${python_libspec} ${python_additional_libs}" >&6; }
 
   if test "$python_enable_shared" != 1; then
     if test "$PORTNAME" = darwin; then
-      # OS X does supply a .dylib even though Py_ENABLE_SHARED does
+      # macOS does supply a .dylib even though Py_ENABLE_SHARED does
       # not get set.  The file detection logic below doesn't succeed
-      # on older OS X versions, so make it explicit.
+      # on older macOS versions, so make it explicit.
       python_enable_shared=1
     elif test "$PORTNAME" = win32; then
       # Windows also needs an explicit override.
@@ -10120,7 +10120,7 @@ else
 fi
 
 elif test "$with_uuid" = e2fs ; then
-  # On OS X, the UUID functions are in libc
+  # On macOS, the UUID functions are in libc
   ac_fn_c_check_func "$LINENO" "uuid_generate" "ac_cv_func_uuid_generate"
 if test "x$ac_cv_func_uuid_generate" = xyes; then :
   UUID_LIBS=""
@@ -12672,7 +12672,7 @@ cat >>confdefs.h <<_ACEOF
 #define HAVE_DECL_STRLCPY $ac_have_decl
 _ACEOF
 
-# This is probably only present on Darwin, but may as well check always
+# This is probably only present on macOS, but may as well check always
 ac_fn_c_check_decl "$LINENO" "F_FULLFSYNC" "ac_cv_have_decl_F_FULLFSYNC" "#include <fcntl.h>
 "
 if test "x$ac_cv_have_decl_F_FULLFSYNC" = xyes; then :
diff --git a/configure.in b/configure.in
index 96d865de9fd..9850d993ffc 100644
--- a/configure.in
+++ b/configure.in
@@ -943,9 +943,9 @@ if test "$with_python" = yes; then
 
   if test "$python_enable_shared" != 1; then
     if test "$PORTNAME" = darwin; then
-      # OS X does supply a .dylib even though Py_ENABLE_SHARED does
+      # macOS does supply a .dylib even though Py_ENABLE_SHARED does
       # not get set.  The file detection logic below doesn't succeed
-      # on older OS X versions, so make it explicit.
+      # on older macOS versions, so make it explicit.
       python_enable_shared=1
     elif test "$PORTNAME" = win32; then
       # Windows also needs an explicit override.
@@ -1182,7 +1182,7 @@ if test "$with_uuid" = bsd ; then
     [UUID_LIBS=""],
     [AC_MSG_ERROR([BSD UUID functions are not present])])
 elif test "$with_uuid" = e2fs ; then
-  # On OS X, the UUID functions are in libc
+  # On macOS, the UUID functions are in libc
   AC_CHECK_FUNC(uuid_generate,
     [UUID_LIBS=""],
     [AC_CHECK_LIB(uuid, uuid_generate,
@@ -1425,8 +1425,8 @@ esac
 if test "$PORTNAME" != "win32"; then
    AC_SYS_LARGEFILE
    dnl Autoconf 2.69's AC_SYS_LARGEFILE believes it's a good idea to #define
-   dnl _DARWIN_USE_64_BIT_INODE, but it isn't: on OS X 10.5 that activates a
-   dnl bug that causes readdir() to sometimes return EINVAL.  On later OS X
+   dnl _DARWIN_USE_64_BIT_INODE, but it isn't: on macOS 10.5 that activates a
+   dnl bug that causes readdir() to sometimes return EINVAL.  On later macOS
    dnl versions where the feature actually works, it's on by default anyway.
    AH_VERBATIM([_DARWIN_USE_64_BIT_INODE],[])
 fi
@@ -1479,7 +1479,7 @@ fi
 
 AC_CHECK_DECLS(fdatasync, [], [], [#include <unistd.h>])
 AC_CHECK_DECLS([strlcat, strlcpy])
-# This is probably only present on Darwin, but may as well check always
+# This is probably only present on macOS, but may as well check always
 AC_CHECK_DECLS(F_FULLFSYNC, [], [], [#include <fcntl.h>])
 
 HAVE_IPV6=no
diff --git a/doc/src/sgml/client-auth.sgml b/doc/src/sgml/client-auth.sgml
index ca262d94523..a0d97ffbac3 100644
--- a/doc/src/sgml/client-auth.sgml
+++ b/doc/src/sgml/client-auth.sgml
@@ -1306,7 +1306,7 @@ omicron         bryanh                  guest1
     socket parameter, or similar mechanisms.  Currently that includes
     <systemitem class="osname">Linux</>,
     most flavors of <systemitem class="osname">BSD</> including
-    <systemitem class="osname">OS X</>,
+    <systemitem class="osname">macOS</>,
     and <systemitem class="osname">Solaris</systemitem>.
    </para>
 
diff --git a/doc/src/sgml/dfunc.sgml b/doc/src/sgml/dfunc.sgml
index 5a368f6df04..ba2684cc3c8 100644
--- a/doc/src/sgml/dfunc.sgml
+++ b/doc/src/sgml/dfunc.sgml
@@ -127,8 +127,8 @@ cc -shared -o foo.so foo.o
 
    <varlistentry>
     <term>
-     <systemitem class="osname">OS X</>
-     <indexterm><primary>OS X</><secondary>shared library</></>
+     <systemitem class="osname">macOS</>
+     <indexterm><primary>macOS</><secondary>shared library</></>
     </term>
     <listitem>
      <para>
diff --git a/doc/src/sgml/docguide.sgml b/doc/src/sgml/docguide.sgml
index 6f896b565f4..48828aff37e 100644
--- a/doc/src/sgml/docguide.sgml
+++ b/doc/src/sgml/docguide.sgml
@@ -275,7 +275,7 @@ apt-get install docbook docbook-dsssl docbook-xsl libxml2-utils openjade1.3 open
   </sect2>
 
   <sect2>
-   <title>OS X</title>
+   <title>macOS</title>
 
    <para>
     If you use MacPorts, the following will get you set up:
diff --git a/doc/src/sgml/install-windows.sgml b/doc/src/sgml/install-windows.sgml
index 50116f315dc..20fc47ae5f4 100644
--- a/doc/src/sgml/install-windows.sgml
+++ b/doc/src/sgml/install-windows.sgml
@@ -51,7 +51,7 @@
   <productname>MinGW-w64</productname>. These tools can also be used to
   cross-compile for 32 bit and 64 bit <productname>Windows</productname>
   targets on other hosts, such as <productname>Linux</productname> and
-  <productname>Darwin</productname>.
+  <productname>macOS</productname>.
   <productname>Cygwin</productname> is not recommended for running a
   production server, and it should only be used for running on
   older versions of <productname>Windows</productname> where
diff --git a/doc/src/sgml/installation.sgml b/doc/src/sgml/installation.sgml
index f6de18ed2d3..5ee28fcf85a 100644
--- a/doc/src/sgml/installation.sgml
+++ b/doc/src/sgml/installation.sgml
@@ -874,7 +874,7 @@ su - postgres
        <listitem>
         <para>
          Build with Bonjour support.  This requires Bonjour support
-         in your operating system.  Recommended on OS X.
+         in your operating system.  Recommended on macOS.
         </para>
        </listitem>
       </varlistentry>
@@ -900,7 +900,7 @@ su - postgres
           <para>
            <option>e2fs</> to use the UUID library created by
            the <literal>e2fsprogs</> project; this library is present in most
-           Linux systems and in OS X, and can be obtained for other
+           Linux systems and in macOS, and can be obtained for other
            platforms as well
           </para>
          </listitem>
@@ -2010,7 +2010,7 @@ kill `cat /usr/local/pgsql/data/postmaster.pid`
   <para>
    <productname>PostgreSQL</> can be expected to work on these operating
    systems: Linux (all recent distributions), Windows (Win2000 SP4 and later),
-   FreeBSD, OpenBSD, NetBSD, OS X, AIX, HP/UX, Solaris,
+   FreeBSD, OpenBSD, NetBSD, macOS, AIX, HP/UX, Solaris,
    and UnixWare.  Other Unix-like systems may also work but are not currently
    being tested.  In most cases, all CPU architectures supported by
    a given operating system will work.  Look in
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 077642878e0..f4007857218 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -2739,7 +2739,7 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
    Currently, the
    <ulink url="https://en.wikipedia.org/wiki/DTrace">DTrace</ulink>
    utility is supported, which, at the time of this writing, is available
-   on Solaris, OS X, FreeBSD, NetBSD, and Oracle Linux.  The
+   on Solaris, macOS, FreeBSD, NetBSD, and Oracle Linux.  The
    <ulink url="http://sourceware.org/systemtap/">SystemTap</ulink> project
    for Linux provides a DTrace equivalent and can also be used.  Supporting other dynamic
    tracing utilities is theoretically possible by changing the definitions for
diff --git a/doc/src/sgml/release-7.4.sgml b/doc/src/sgml/release-7.4.sgml
index 5a4c52d4c2d..e42be5b89d0 100644
--- a/doc/src/sgml/release-7.4.sgml
+++ b/doc/src/sgml/release-7.4.sgml
@@ -268,7 +268,7 @@
      </para>
 
      <para>
-      This behavior has been observed on BSD-derived kernels including OS X.
+      This behavior has been observed on BSD-derived kernels including macOS.
       It resulted in an entirely-misleading startup failure complaining that
       the shared memory request size was too large.
      </para>
@@ -2437,7 +2437,7 @@ aggregate plan</para></listitem>
 <listitem><para>Pretty-print UNION queries correctly</para></listitem>
 <listitem><para>Make psql handle <literal>\r\n</> newlines properly in COPY IN</para></listitem>
 <listitem><para><application>pg_dump</> handled ACLs with grant options incorrectly</para></listitem>
-<listitem><para>Fix thread support for OS X and Solaris</para></listitem>
+<listitem><para>Fix thread support for macOS and Solaris</para></listitem>
 <listitem><para>Updated JDBC driver (build 215) with various fixes</para></listitem>
 <listitem><para>ECPG fixes</para></listitem>
 <listitem><para>Translation updates (various contributors)</para></listitem>
@@ -2627,7 +2627,7 @@ memory</> error during <command>COPY IN</></para></listitem>
 TABLE AS</> from tables without OIDs</para></listitem>
 <listitem><para>Fix problems with <filename>alter_table</> regression test
 during parallel testing</para></listitem>
-<listitem><para>Fix problems with hitting open file limit, especially on OS X (Tom)</para></listitem>
+<listitem><para>Fix problems with hitting open file limit, especially on macOS (Tom)</para></listitem>
 <listitem><para>Partial fix for Turkish-locale issues</para>
 <para>initdb will succeed now in Turkish locale, but there are still some
 inconveniences associated with the <literal>i/I</> problem.</para></listitem>
@@ -3256,7 +3256,7 @@ DROP SCHEMA information_schema CASCADE;
     </para>
    </listitem>
 
-   <listitem><para>Enable PAM for Mac OS X (Aaron Hillegass)</para></listitem>
+   <listitem><para>Enable PAM for macOS (Aaron Hillegass)</para></listitem>
 
    <listitem>
     <para>Make B-tree indexes fully WAL-safe (Tom)</para>
@@ -3539,9 +3539,9 @@ DROP SCHEMA information_schema CASCADE;
    </listitem>
 
    <listitem>
-    <para>Add Mac OS X Rendezvous server support (Chris Campbell)</para>
+    <para>Add macOS Rendezvous server support (Chris Campbell)</para>
     <para>
-     This allows Mac OS X hosts to query the network for available
+     This allows macOS hosts to query the network for available
      <productname>PostgreSQL</productname> servers.
     </para>
    </listitem>
@@ -4561,7 +4561,7 @@ DROP SCHEMA information_schema CASCADE;
    <listitem><para>Fix locking code for s390x CPU (64-bit) (Tom)</para></listitem>
    <listitem><para>Allow OpenBSD to use local ident credentials (William Ahern)</para></listitem>
    <listitem><para>Make query plan trees read-only to executor (Tom)</para></listitem>
-   <listitem><para>Add Darwin startup scripts (David Wheeler)</para></listitem>
+   <listitem><para>Add macOS startup scripts (David Wheeler)</para></listitem>
    <listitem><para>Allow libpq to compile with Borland C++ compiler (Lester Godwin, Karl Waclawek)</para></listitem>
    <listitem><para>Use our own version of <function>getopt_long()</function> if needed (Peter)</para></listitem>
    <listitem><para>Convert administration scripts to C (Peter)</para></listitem>
diff --git a/doc/src/sgml/release-8.0.sgml b/doc/src/sgml/release-8.0.sgml
index 299c34e0f07..becd5090cc0 100644
--- a/doc/src/sgml/release-8.0.sgml
+++ b/doc/src/sgml/release-8.0.sgml
@@ -345,7 +345,7 @@
      </para>
 
      <para>
-      This behavior has been observed on BSD-derived kernels including OS X.
+      This behavior has been observed on BSD-derived kernels including macOS.
       It resulted in an entirely-misleading startup failure complaining that
       the shared memory request size was too large.
      </para>
@@ -1715,7 +1715,7 @@
 
      <para>
       While this could theoretically happen anywhere, no standard build of
-      Perl did things this way ... until <productname>Mac OS X</> 10.5.
+      Perl did things this way ... until <productname>macOS</> 10.5.
      </para>
     </listitem>
 
@@ -2449,7 +2449,7 @@ Win32 to match the backend (Andrew)</para></listitem>
 (Bruce)</para></listitem>
 
 <listitem><para>Fix <application>pgxs</> <literal>-L</> library path
-specification for Win32, Cygwin, OS X, AIX (Bruce)</para></listitem>
+specification for Win32, Cygwin, macOS, AIX (Bruce)</para></listitem>
 
 <listitem><para>Check that SID is enabled while checking for Win32 admin
 privileges (Magnus)</para></listitem>
@@ -5224,7 +5224,7 @@ typedefs (Michael)</para></listitem>
 
      <listitem>
       <para>
-       Improvements to the Mac OS X startup scripts (Ray A.)
+       Improvements to the macOS startup scripts (Ray A.)
       </para>
      </listitem>
 
@@ -5328,7 +5328,7 @@ typedefs (Michael)</para></listitem>
 
      <listitem>
       <para>
-       Make libpq and ECPG build as proper shared libraries on OS X (Tom)
+       Make libpq and ECPG build as proper shared libraries on macOS (Tom)
       </para>
      </listitem>
 
diff --git a/doc/src/sgml/release-8.1.sgml b/doc/src/sgml/release-8.1.sgml
index 0cb5587e9b2..05b07ade99f 100644
--- a/doc/src/sgml/release-8.1.sgml
+++ b/doc/src/sgml/release-8.1.sgml
@@ -572,7 +572,7 @@
      </para>
 
      <para>
-      This behavior has been observed on BSD-derived kernels including OS X.
+      This behavior has been observed on BSD-derived kernels including macOS.
       It resulted in an entirely-misleading startup failure complaining that
       the shared memory request size was too large.
      </para>
@@ -2188,7 +2188,7 @@
 
      <para>
       While this could theoretically happen anywhere, no standard build of
-      Perl did things this way ... until <productname>Mac OS X</> 10.5.
+      Perl did things this way ... until <productname>macOS</> 10.5.
      </para>
     </listitem>
 
@@ -2730,7 +2730,7 @@
 
     <listitem>
      <para>
-      Fix for Darwin (OS X) compilation (Tom)
+      Fix for macOS (Darwin) compilation (Tom)
      </para>
     </listitem>
 
@@ -3104,7 +3104,7 @@ Win32 to match the backend (Andrew)</para></listitem>
 (Bruce)</para></listitem>
 
 <listitem><para>Fix <application>pgxs</> <literal>-L</> library path
-specification for Win32, Cygwin, OS X, AIX (Bruce)</para></listitem>
+specification for Win32, Cygwin, macOS, AIX (Bruce)</para></listitem>
 
 <listitem><para>Check that SID is enabled while checking for Win32 admin
 privileges (Magnus)</para></listitem>
@@ -5225,7 +5225,7 @@ SELECT CURRENT_TIMESTAMP AT TIME ZONE 'Europe/London';
      <listitem>
       <para>
        Add support for <literal>fsync_writethrough</literal> on
-       Darwin (Chris Campbell)
+       macOS (Chris Campbell)
       </para>
      </listitem>
 
diff --git a/doc/src/sgml/release-8.2.sgml b/doc/src/sgml/release-8.2.sgml
index 7f6a74bac9f..2d21728cf7a 100644
--- a/doc/src/sgml/release-8.2.sgml
+++ b/doc/src/sgml/release-8.2.sgml
@@ -1487,7 +1487,7 @@
      </para>
 
      <para>
-      This behavior has been observed on BSD-derived kernels including OS X.
+      This behavior has been observed on BSD-derived kernels including macOS.
       It resulted in an entirely-misleading startup failure complaining that
       the shared memory request size was too large.
      </para>
@@ -3765,7 +3765,7 @@
 
      <para>
       While this could theoretically happen anywhere, no standard build of
-      Perl did things this way ... until <productname>Mac OS X</> 10.5.
+      Perl did things this way ... until <productname>macOS</> 10.5.
      </para>
     </listitem>
 
diff --git a/doc/src/sgml/release-8.3.sgml b/doc/src/sgml/release-8.3.sgml
index b56edb01024..b1b5d4875c7 100644
--- a/doc/src/sgml/release-8.3.sgml
+++ b/doc/src/sgml/release-8.3.sgml
@@ -3075,7 +3075,7 @@
      </para>
 
      <para>
-      This behavior has been observed on BSD-derived kernels including OS X.
+      This behavior has been observed on BSD-derived kernels including macOS.
       It resulted in an entirely-misleading startup failure complaining that
       the shared memory request size was too large.
      </para>
@@ -8396,7 +8396,7 @@ current_date &lt; 2017-11-17
      <listitem>
       <para>
        Use <acronym>SYSV</> semaphores rather than POSIX on Darwin
-       &gt;= 6.0, i.e., OS X 10.2 and up (Chris Marcellino)
+       &gt;= 6.0, i.e., macOS 10.2 and up (Chris Marcellino)
       </para>
      </listitem>
 
diff --git a/doc/src/sgml/release-8.4.sgml b/doc/src/sgml/release-8.4.sgml
index 8b16c9e9d3c..0d0478855ed 100644
--- a/doc/src/sgml/release-8.4.sgml
+++ b/doc/src/sgml/release-8.4.sgml
@@ -240,7 +240,7 @@
 
     <listitem>
      <para>
-      Fix linking of <application>libpython</> on OS X (Tom Lane)
+      Fix linking of <application>libpython</> on macOS (Tom Lane)
      </para>
 
      <para>
@@ -5334,7 +5334,7 @@
      </para>
 
      <para>
-      This behavior has been observed on BSD-derived kernels including OS X.
+      This behavior has been observed on BSD-derived kernels including macOS.
       It resulted in an entirely-misleading startup failure complaining that
       the shared memory request size was too large.
      </para>
@@ -9764,7 +9764,7 @@ WITH w AS (SELECT * FROM foo) SELECT * FROM w, bar ... FOR UPDATE
 
      <listitem>
       <para>
-       Enable <application>DTrace</> support on <application>Mac OS X
+       Enable <application>DTrace</> support on <application>macOS
        Leopard</> and other non-Solaris platforms (Robert Lor)
       </para>
      </listitem>
diff --git a/doc/src/sgml/release-9.0.sgml b/doc/src/sgml/release-9.0.sgml
index 61dce9fd785..2238b537456 100644
--- a/doc/src/sgml/release-9.0.sgml
+++ b/doc/src/sgml/release-9.0.sgml
@@ -1541,7 +1541,7 @@
 
     <listitem>
      <para>
-      Warn if OS X's <function>setlocale()</> starts an unwanted extra
+      Warn if macOS's <function>setlocale()</> starts an unwanted extra
       thread inside the postmaster (Noah Misch)
      </para>
     </listitem>
@@ -2093,7 +2093,7 @@
 
     <listitem>
      <para>
-      Fix linking of <application>libpython</> on OS X (Tom Lane)
+      Fix linking of <application>libpython</> on macOS (Tom Lane)
      </para>
 
      <para>
@@ -5895,7 +5895,7 @@
 
     <listitem>
      <para>
-      Fix incorrect quoting of log file name in Mac OS X start script
+      Fix incorrect quoting of log file name in macOS start script
       (Sidar Lopez)
      </para>
     </listitem>
@@ -10745,7 +10745,7 @@ if TG_OP = 'INSERT' and NEW.col1 = ... then
       </para>
 
       <para>
-       Bonjour support now requires <productname>OS X</> 10.3 or later.
+       Bonjour support now requires <productname>macOS</> 10.3 or later.
        The older API has been deprecated by Apple.
       </para>
      </listitem>
diff --git a/doc/src/sgml/release-9.1.sgml b/doc/src/sgml/release-9.1.sgml
index a66ca0d5b3d..26b709056f9 100644
--- a/doc/src/sgml/release-9.1.sgml
+++ b/doc/src/sgml/release-9.1.sgml
@@ -599,7 +599,7 @@ Branch: REL9_1_STABLE [354b3a3ac] 2016-06-19 14:01:17 -0400
 
      <para>
       This dodges a portability problem on FreeBSD-derived platforms
-      (including OS X).
+      (including macOS).
      </para>
     </listitem>
 
@@ -2937,7 +2937,7 @@ Branch: REL9_0_STABLE [9d6af7367] 2015-08-15 11:02:34 -0400
 
     <listitem>
      <para>
-      Warn if OS X's <function>setlocale()</> starts an unwanted extra
+      Warn if macOS's <function>setlocale()</> starts an unwanted extra
       thread inside the postmaster (Noah Misch)
      </para>
     </listitem>
@@ -3574,7 +3574,7 @@ Branch: REL9_0_STABLE [9d6af7367] 2015-08-15 11:02:34 -0400
 
     <listitem>
      <para>
-      Fix linking of <application>libpython</> on OS X (Tom Lane)
+      Fix linking of <application>libpython</> on macOS (Tom Lane)
      </para>
 
      <para>
@@ -8443,7 +8443,7 @@ Branch: REL9_0_STABLE [9d6af7367] 2015-08-15 11:02:34 -0400
 
     <listitem>
      <para>
-      Fix incorrect quoting of log file name in Mac OS X start script
+      Fix incorrect quoting of log file name in macOS start script
       (Sidar Lopez)
      </para>
     </listitem>
diff --git a/doc/src/sgml/release-9.2.sgml b/doc/src/sgml/release-9.2.sgml
index c801f98c3fc..0f6e3d127f5 100644
--- a/doc/src/sgml/release-9.2.sgml
+++ b/doc/src/sgml/release-9.2.sgml
@@ -629,7 +629,7 @@
 
      <para>
       This dodges a portability problem on FreeBSD-derived platforms
-      (including OS X).
+      (including macOS).
      </para>
     </listitem>
 
@@ -3190,7 +3190,7 @@ Branch: REL9_2_STABLE [6b700301c] 2015-02-17 16:03:00 +0100
 
     <listitem>
      <para>
-      Warn if OS X's <function>setlocale()</> starts an unwanted extra
+      Warn if macOS's <function>setlocale()</> starts an unwanted extra
       thread inside the postmaster (Noah Misch)
      </para>
     </listitem>
@@ -3899,7 +3899,7 @@ Branch: REL9_2_STABLE [6b700301c] 2015-02-17 16:03:00 +0100
 
     <listitem>
      <para>
-      Fix linking of <application>libpython</> on OS X (Tom Lane)
+      Fix linking of <application>libpython</> on macOS (Tom Lane)
      </para>
 
      <para>
diff --git a/doc/src/sgml/release-9.3.sgml b/doc/src/sgml/release-9.3.sgml
index c75f1109e1e..e321f4b31c9 100644
--- a/doc/src/sgml/release-9.3.sgml
+++ b/doc/src/sgml/release-9.3.sgml
@@ -812,7 +812,7 @@ Branch: REL9_2_STABLE [37f30b251] 2016-04-18 13:19:52 -0400
 
      <para>
       This dodges a portability problem on FreeBSD-derived platforms
-      (including OS X).
+      (including macOS).
      </para>
     </listitem>
 
@@ -3021,7 +3021,7 @@ Branch: REL9_0_STABLE [4dddf8552] 2015-05-21 20:41:55 -0400
 
     <listitem>
      <para>
-      Silence some build warnings on OS X (Tom Lane)
+      Silence some build warnings on macOS (Tom Lane)
      </para>
     </listitem>
 
@@ -4092,7 +4092,7 @@ Branch: REL9_0_STABLE [2e4946169] 2015-01-07 22:46:20 -0500
 
     <listitem>
      <para>
-      Warn if OS X's <function>setlocale()</> starts an unwanted extra
+      Warn if macOS's <function>setlocale()</> starts an unwanted extra
       thread inside the postmaster (Noah Misch)
      </para>
     </listitem>
@@ -5743,7 +5743,7 @@ Branch: REL8_4_STABLE [ae41bb4be] 2014-05-30 18:18:32 -0400
 
     <listitem>
      <para>
-      Fix linking of <application>libpython</> on OS X (Tom Lane)
+      Fix linking of <application>libpython</> on macOS (Tom Lane)
      </para>
 
      <para>
@@ -10710,7 +10710,7 @@ ALTER EXTENSION hstore UPDATE;
       <listitem>
        <para>
         Add <link linkend="docguide-toolsets">instructions</link> for setting
-        up the documentation tool chain on Mac <productname>OS X</>
+        up the documentation tool chain on <productname>macOS</>
         (Peter Eisentraut)
        </para>
       </listitem>
diff --git a/doc/src/sgml/release-9.4.sgml b/doc/src/sgml/release-9.4.sgml
index 443c772846b..51896924c99 100644
--- a/doc/src/sgml/release-9.4.sgml
+++ b/doc/src/sgml/release-9.4.sgml
@@ -929,7 +929,7 @@ Branch: REL9_1_STABLE [de887cc8a] 2016-05-25 19:39:49 -0400
 
      <para>
       This dodges a portability problem on FreeBSD-derived platforms
-      (including OS X).
+      (including macOS).
      </para>
     </listitem>
 
@@ -5254,7 +5254,7 @@ Branch: REL9_3_STABLE [6347bdb31] 2015-04-05 13:01:55 -0400
 
     <listitem>
      <para>
-      Silence some build warnings on OS X (Tom Lane)
+      Silence some build warnings on macOS (Tom Lane)
      </para>
     </listitem>
 
@@ -5813,7 +5813,7 @@ Branch: REL9_0_STABLE [2e4946169] 2015-01-07 22:46:20 -0500
 
     <listitem>
      <para>
-      Warn if OS X's <function>setlocale()</> starts an unwanted extra
+      Warn if macOS's <function>setlocale()</> starts an unwanted extra
       thread inside the postmaster (Noah Misch)
      </para>
     </listitem>
diff --git a/doc/src/sgml/release-9.5.sgml b/doc/src/sgml/release-9.5.sgml
index fa3537de105..c3f0f7051eb 100644
--- a/doc/src/sgml/release-9.5.sgml
+++ b/doc/src/sgml/release-9.5.sgml
@@ -2023,7 +2023,7 @@ Branch: REL9_1_STABLE [e56acbe2a] 2016-02-10 19:30:12 -0500
 
      <para>
       This dodges a portability problem on FreeBSD-derived platforms
-      (including OS X).
+      (including macOS).
      </para>
     </listitem>
 
diff --git a/doc/src/sgml/release-old.sgml b/doc/src/sgml/release-old.sgml
index ec8e43f6eae..cd9b3db35a3 100644
--- a/doc/src/sgml/release-old.sgml
+++ b/doc/src/sgml/release-old.sgml
@@ -3299,7 +3299,7 @@ New BeOS port (David Reid, Cyril Velter)
 Add proofreader's changes to docs (Addison-Wesley, Bruce)
 New Alpha spinlock code (Adriaan Joubert, Compaq)
 UnixWare port overhaul (Peter E)
-New Darwin/Mac OS X port (Peter Bierman, Bruce Hartzler)
+New macOS (Darwin) port (Peter Bierman, Bruce Hartzler)
 New FreeBSD Alpha port (Alfred)
 Overhaul shared memory segments (Tom)
 Add IBM S/390 support (Neale Ferguson)
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index ef0139c3659..88ec120841f 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1006,12 +1006,12 @@ option        SEMMAP=256
 
 
      <varlistentry>
-      <term><systemitem class="osname">OS X</>
-      <indexterm><primary>OS X</><secondary>IPC configuration</></>
+      <term><systemitem class="osname">macOS</>
+      <indexterm><primary>macOS</><secondary>IPC configuration</></>
       </term>
       <listitem>
        <para>
-        The recommended method for configuring shared memory in OS X
+        The recommended method for configuring shared memory in macOS
         is to create a file named <filename>/etc/sysctl.conf</>,
         containing variable assignments such as:
 <programlisting>
@@ -1021,13 +1021,13 @@ kern.sysv.shmmni=32
 kern.sysv.shmseg=8
 kern.sysv.shmall=1024
 </programlisting>
-        Note that in some OS X versions,
+        Note that in some macOS versions,
         <emphasis>all five</> shared-memory parameters must be set in
         <filename>/etc/sysctl.conf</>, else the values will be ignored.
        </para>
 
        <para>
-        Beware that recent releases of OS X ignore attempts to set
+        Beware that recent releases of macOS ignore attempts to set
         <varname>SHMMAX</> to a value that isn't an exact multiple of 4096.
        </para>
 
@@ -1036,7 +1036,7 @@ kern.sysv.shmall=1024
        </para>
 
        <para>
-        In older OS X versions, you will need to reboot to have changes in the
+        In older macOS versions, you will need to reboot to have changes in the
         shared memory parameters take effect.  As of 10.5 it is possible to
         change all but <varname>SHMMNI</> on the fly, using
         <application>sysctl</>.  But it's still best to set up your preferred
@@ -1045,7 +1045,7 @@ kern.sysv.shmall=1024
        </para>
 
        <para>
-        The file <filename>/etc/sysctl.conf</> is only honored in OS X
+        The file <filename>/etc/sysctl.conf</> is only honored in macOS
         10.3.9 and later.  If you are running a previous 10.3.x release,
         you must edit the file <filename>/etc/rc</>
         and change the values in the following commands:
@@ -1057,12 +1057,12 @@ sysctl -w kern.sysv.shmseg
 sysctl -w kern.sysv.shmall
 </programlisting>
         Note that
-        <filename>/etc/rc</> is usually overwritten by OS X system updates,
+        <filename>/etc/rc</> is usually overwritten by macOS system updates,
         so you should expect to have to redo these edits after each update.
        </para>
 
        <para>
-        In OS X 10.2 and earlier, instead edit these commands in the file
+        In macOS 10.2 and earlier, instead edit these commands in the file
         <filename>/System/Library/StartupItems/SystemTuning/SystemTuning</>.
        </para>
       </listitem>
diff --git a/doc/src/sgml/uuid-ossp.sgml b/doc/src/sgml/uuid-ossp.sgml
index e275febe4e6..227d4a839c8 100644
--- a/doc/src/sgml/uuid-ossp.sgml
+++ b/doc/src/sgml/uuid-ossp.sgml
@@ -169,7 +169,7 @@ SELECT uuid_generate_v3(uuid_ns_url(), 'http://www.postgresql.org');
    platforms.  <filename>uuid-ossp</> can now be built without the OSSP
    library on some platforms.  On FreeBSD, NetBSD, and some other BSD-derived
    platforms, suitable UUID creation functions are included in the
-   core <filename>libc</> library.  On Linux, OS X, and some other
+   core <filename>libc</> library.  On Linux, macOS, and some other
    platforms, suitable functions are provided in the <filename>libuuid</>
    library, which originally came from the <literal>e2fsprogs</> project
    (though on modern Linux it is considered part
diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml
index 9ae65477218..fe3b588c721 100644
--- a/doc/src/sgml/wal.sgml
+++ b/doc/src/sgml/wal.sgml
@@ -115,7 +115,7 @@
 
     <listitem>
       <para>
-        On <productname>OS X</productname>, write caching can be prevented by
+        On <productname>macOS</productname>, write caching can be prevented by
         setting <varname>wal_sync_method</> to <literal>fsync_writethrough</>.
       </para>
     </listitem>
diff --git a/src/Makefile.shlib b/src/Makefile.shlib
index 924d21f443c..de93f416393 100644
--- a/src/Makefile.shlib
+++ b/src/Makefile.shlib
@@ -323,7 +323,7 @@ endif
 endif # shlib_major
 
 # Where possible, restrict the symbols exported by the library to just the
-# official list, so as to avoid unintentional ABI changes.  On recent Darwin
+# official list, so as to avoid unintentional ABI changes.  On recent macOS
 # this also quiets multiply-defined-symbol warnings in programs that use
 # libpgport along with libpq.
 ifneq (,$(SHLIB_EXPORTS))
diff --git a/src/backend/Makefile b/src/backend/Makefile
index 3b08defe2bc..4946d37929c 100644
--- a/src/backend/Makefile
+++ b/src/backend/Makefile
@@ -26,8 +26,8 @@ include $(srcdir)/common.mk
 # As of 1/2010:
 # The probes.o file is necessary for dtrace support on Solaris, and on recent
 # versions of systemtap.  (Older systemtap releases just produce an empty
-# file, but that's okay.)  However, OS X's dtrace doesn't use it and doesn't
-# even recognize the -G option.  So, build probes.o except on Darwin.
+# file, but that's okay.)  However, macOS's dtrace doesn't use it and doesn't
+# even recognize the -G option.  So, build probes.o except on macOS.
 # This might need adjustment as other platforms add dtrace support.
 ifneq ($(PORTNAME), darwin)
 ifeq ($(enable_dtrace), yes)
diff --git a/src/backend/port/dynloader/darwin.c b/src/backend/port/dynloader/darwin.c
index a83c614f4f1..7b6b48d14ac 100644
--- a/src/backend/port/dynloader/darwin.c
+++ b/src/backend/port/dynloader/darwin.c
@@ -1,5 +1,5 @@
 /*
- * Dynamic loading support for Darwin
+ * Dynamic loading support for macOS (Darwin)
  *
  * If dlopen() is available (Darwin 10.3 and later), we just use it.
  * Otherwise we emulate it with the older, now deprecated, NSLinkModule API.
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 40995580af3..0c0a609735e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -1273,7 +1273,7 @@ PostmasterMain(int argc, char *argv[])
 #ifdef HAVE_PTHREAD_IS_THREADED_NP
 
 	/*
-	 * On Darwin, libintl replaces setlocale() with a version that calls
+	 * On macOS, libintl replaces setlocale() with a version that calls
 	 * CFLocaleCopyCurrent() when its second argument is "" and every relevant
 	 * environment variable is unset or empty.  CFLocaleCopyCurrent() makes
 	 * the process multithreaded.  The postmaster calls sigprocmask() and
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 582d3e460b2..260a5aac496 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -1844,8 +1844,8 @@ varstr_sortsupport(SortSupport ssup, Oid collid, bool bpchar)
 	 * Even apart from the risk of broken locales, it's possible that there
 	 * are platforms where the use of abbreviated keys should be disabled at
 	 * compile time.  Having only 4 byte datums could make worst-case
-	 * performance drastically more likely, for example.  Moreover, Darwin's
-	 * strxfrm() implementations is known to not effectively concentrate a
+	 * performance drastically more likely, for example.  Moreover, macOS's
+	 * strxfrm() implementation is known to not effectively concentrate a
 	 * significant amount of entropy from the original string in earlier
 	 * transformed blobs.  It's possible that other supported platforms are
 	 * similarly encumbered.  So, if we ever get past disabling this
diff --git a/src/backend/utils/misc/ps_status.c b/src/backend/utils/misc/ps_status.c
index c50be8aab65..a889b170c83 100644
--- a/src/backend/utils/misc/ps_status.c
+++ b/src/backend/utils/misc/ps_status.c
@@ -223,8 +223,8 @@ save_ps_display_args(int argc, char **argv)
 #if defined(__darwin__)
 
 		/*
-		 * Darwin (and perhaps other NeXT-derived platforms?) has a static
-		 * copy of the argv pointer, which we may fix like so:
+		 * macOS (and perhaps other NeXT-derived platforms?) has a static copy
+		 * of the argv pointer, which we may fix like so:
 		 */
 		*_NSGetArgv() = new_argv;
 #endif
diff --git a/src/backend/utils/probes.d b/src/backend/utils/probes.d
index 976774e795e..2f92dfa9adb 100644
--- a/src/backend/utils/probes.d
+++ b/src/backend/utils/probes.d
@@ -12,7 +12,7 @@
  * Typedefs used in PostgreSQL.
  *
  * NOTE: Do not use system-provided typedefs (e.g. uintptr_t, uint32_t, etc)
- * in probe definitions, as they cause compilation errors on Mac OS X 10.5.
+ * in probe definitions, as they cause compilation errors on macOS 10.5.
  */
 #define LocalTransactionId unsigned int
 #define LWLockMode int
diff --git a/src/bin/psql/input.c b/src/bin/psql/input.c
index 2359b11dcdd..a7d017a2d5a 100644
--- a/src/bin/psql/input.c
+++ b/src/bin/psql/input.c
@@ -411,7 +411,7 @@ saveHistory(char *fname, int max_lines)
 
 	/*
 	 * Suppressing the write attempt when HISTFILE is set to /dev/null may
-	 * look like a negligible optimization, but it's necessary on e.g. Darwin,
+	 * look like a negligible optimization, but it's necessary on e.g. macOS,
 	 * where write_history will fail because it tries to chmod the target
 	 * file.
 	 */
diff --git a/src/include/port/darwin.h b/src/include/port/darwin.h
index 29c4b91d8ce..15fb69d6dbb 100644
--- a/src/include/port/darwin.h
+++ b/src/include/port/darwin.h
@@ -2,7 +2,7 @@
 
 #define __darwin__	1
 
-#if HAVE_DECL_F_FULLFSYNC		/* not present before OS X 10.3 */
+#if HAVE_DECL_F_FULLFSYNC		/* not present before macOS 10.3 */
 #define HAVE_FSYNC_WRITETHROUGH
 
 #endif
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 9668b52103f..f3a9e5a83fe 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -1252,7 +1252,7 @@ setKeepalivesIdle(PGconn *conn)
 	}
 #else
 #ifdef TCP_KEEPALIVE
-	/* Darwin uses TCP_KEEPALIVE rather than TCP_KEEPIDLE */
+	/* macOS uses TCP_KEEPALIVE rather than TCP_KEEPIDLE */
 	if (setsockopt(conn->sock, IPPROTO_TCP, TCP_KEEPALIVE,
 				   (char *) &idle, sizeof(idle)) < 0)
 	{
diff --git a/src/port/README b/src/port/README
index 58fb32d9f94..4ae96da0158 100644
--- a/src/port/README
+++ b/src/port/README
@@ -28,5 +28,5 @@ applications.
 from libpgport are linked first.  This avoids having applications
 dependent on symbols that are _used_ by libpq, but not intended to be
 exported by libpq.  libpq's libpgport usage changes over time, so such a
-dependency is a problem.  Win32, Linux, and Darwin use an export list to
+dependency is a problem.  Windows, Linux, and macOS use an export list to
 control the symbols exported by libpq.
diff --git a/src/port/chklocale.c b/src/port/chklocale.c
index 3c0ef6a2530..915821a4e91 100644
--- a/src/port/chklocale.c
+++ b/src/port/chklocale.c
@@ -395,7 +395,7 @@ pg_get_encoding_from_locale(const char *ctype, bool write_message)
 #ifdef __darwin__
 
 	/*
-	 * Current OS X has many locales that report an empty string for CODESET,
+	 * Current macOS has many locales that report an empty string for CODESET,
 	 * but they all seem to actually use UTF-8.
 	 */
 	if (strlen(sys) == 0)
diff --git a/src/template/darwin b/src/template/darwin
index 542f706b0fa..ea6d3b0b042 100644
--- a/src/template/darwin
+++ b/src/template/darwin
@@ -1,9 +1,12 @@
 # src/template/darwin
 
-# Select appropriate semaphore support.  Darwin 6.0 (Mac OS X 10.2) and up
-# support System V semaphores; before that we have to use POSIX semaphores,
-# which are less good for our purposes because they eat a file descriptor
-# per backend per max_connection slot.
+# Note: Darwin is the original code name for macOS, also known as OS X.
+# We still use "darwin" as the port name, partly because config.guess does.
+
+# Select appropriate semaphore support.  Darwin 6.0 (macOS 10.2) and up
+# support System V semaphores; before that we have to use named POSIX
+# semaphores, which are less good for our purposes because they eat a
+# file descriptor per backend per max_connection slot.
 case $host_os in
   darwin[015].*)
     USE_NAMED_POSIX_SEMAPHORES=1
diff --git a/src/test/regress/pg_regress.c b/src/test/regress/pg_regress.c
index 1154d4c300e..b28cb0b1e1e 100644
--- a/src/test/regress/pg_regress.c
+++ b/src/test/regress/pg_regress.c
@@ -738,9 +738,9 @@ initialize_environment(void)
 		/*
 		 * Most platforms have adopted the POSIX locale as their
 		 * implementation-defined default locale.  Exceptions include native
-		 * Windows, Darwin with --enable-nls, and Cygwin with --enable-nls.
+		 * Windows, macOS with --enable-nls, and Cygwin with --enable-nls.
 		 * (Use of --enable-nls matters because libintl replaces setlocale().)
-		 * Also, PostgreSQL does not support Darwin with locale environment
+		 * Also, PostgreSQL does not support macOS with locale environment
 		 * variables unset; see PostmasterMain().
 		 */
 #if defined(WIN32) || defined(__CYGWIN__) || defined(__darwin__)
diff --git a/src/tools/find_typedef b/src/tools/find_typedef
index fee0fb5152d..24e9b76651d 100755
--- a/src/tools/find_typedef
+++ b/src/tools/find_typedef
@@ -13,7 +13,7 @@
 # find both .o files and executables.  Therefore, ignore error messages about
 # unsuitable files being fed to objdump.
 #
-# This is known to work on Linux and on some BSDen, including Mac OS X.
+# This is known to work on Linux and on some BSDen, including macOS.
 #
 # Caution: on the platforms we use, this only prints typedefs that are used
 # to declare at least one variable or struct field.  If you have say