diff options
| -rw-r--r-- | src/Makefile.global.in | 45 |
1 files changed, 23 insertions, 22 deletions
diff --git a/src/Makefile.global.in b/src/Makefile.global.in index d290116f8cd..cb5f31c3eab 100644 --- a/src/Makefile.global.in +++ b/src/Makefile.global.in @@ -549,37 +549,38 @@ install-strip: # allows parallel make across directories and lets make -k and -q work # correctly. +# We need the $(eval) function and order-only prerequisites, which are +# available in GNU make 3.80. That also happens to be the version +# where the .VARIABLES variable was introduced, so this is a simple check. +ifndef .VARIABLES +$(error GNU make 3.80 or newer is required. You are using version $(MAKE_VERSION)) +endif + # This function is only for internal use below. It should be called -# with $(eval). It will set up a target so that it recurses into -# subdirectories. +# using $(eval). It will set up a target so that it recurses into +# a given subdirectory. Note that to avoid a nasty bug in make 3.80, +# it is important that the expansion of this function not exceed about +# 200 bytes. This is why we make it apply to just one subdirectory at a +# time, rather than to a list of subdirectories. # $1: target name, e.g., all -# $2: list of subdirs +# $2: subdir name # $3: target to run in subdir, usually same as $1 define _create_recursive_target -.PHONY: $(patsubst %,$(1)-%-recursive,$(2)) -$(1): $(patsubst %,$(1)-%-recursive,$(2)) -$(2:%=$(1)-%-recursive): - $$(MAKE) -C $$(patsubst $(1)-%-recursive,%,$$@) $(3) +.PHONY: $(1)-$(2)-recurse +$(1): $(1)-$(2)-recurse +$(1)-$(2)-recurse: + $$(MAKE) -C $(2) $(3) endef # Note that the use of $$ on the last line above is important; we want -# those variables/functions to be evaluated when the rule is run, not -# when the $(eval) is run to create the rule. In the case of -# $$(MAKE), this is necessary to get make -q working. +# $(MAKE) to be evaluated when the rule is run, not when the $(eval) is run +# to create the rule. This is necessary to get make -q working. -# Call this function in a makefile. In the normal case it doesn't -# need any arguments. +# Call this function in a makefile that needs to recurse into subdirectories. +# In the normal case all arguments can be defaulted. # $1: targets to make recursive (defaults to list of standard targets) # $2: list of subdirs (defaults to SUBDIRS variable) -# $3: target to run in subdir (defaults to $1) -recurse = $(foreach target,$(if $1,$1,$(standard_targets)),$(eval $(call _create_recursive_target,$(target),$(if $2,$2,$(SUBDIRS)),$(if $3,$3,$(target))))) - -# We need the $(eval) function and order-only prerequisites, which are -# available in GNU make 3.80. That also happens to be the version -# where the .VARIABLES variable was introduced, so this is a simple -# check. -ifndef .VARIABLES -$(error GNU make 3.80 or newer is required. You are using version $(MAKE_VERSION)) -endif +# $3: target to run in subdir (defaults to current element of $1) +recurse = $(foreach target,$(if $1,$1,$(standard_targets)),$(foreach subdir,$(if $2,$2,$(SUBDIRS)),$(eval $(call _create_recursive_target,$(target),$(subdir),$(if $3,$3,$(target)))))) ########################################################################## |