[GHC] #12624: Un-revert PosixSource.h cleanup

[GHC]

#12624: Un-revert PosixSource.h cleanup
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        Reporter:  bgamari           |                Owner:
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by angerman):

 As @kgardas provided via email:

 the core of the issue is this:

 > Oracle's Solaris 11 supports max:
 >
 > #define _POSIX_C_SOURCE 200112L
 > #define _XOPEN_SOURCE   600

 how the feature_tests.h likely looks can be found at
 https://raw.githubusercontent.com/illumos/illumos-
 gate/7c478bd95313f5f23a4c958a745db2134aa03244/usr/src/uts/common/sys/feature_tests.h

 I'm wondering if we can get away without platform ifdefs :-/

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12624#comment:5>
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