Merge of r4004, r4005:

Merge of r4004, r4005:

Solaris related fixes:

*) Detect POSIX semaphores in librt on Solaris (ticket #3).
   Patch by Denis Ivanov.
*) Lower optimization level for Sun Studio before 12.1.
   At least Sun Studio 12 has problems with bit-fields exposed by nginx code
   (caught by test suite).  They seems to be fixed in Sun Studio 12.1.  As a
   workaround use "-fast -xalias_level=any" for older versions, it resolves
   the problem.