[GHC] #12858: clock_gettime support on OS X is a nightmare

[GHC]

#12858: clock_gettime support on OS X is a nightmare
----------------------------------------+---------------------------------
           Reporter:  bgamari           |             Owner:
               Type:  bug               |            Status:  new
           Priority:  high              |         Milestone:  8.0.2
          Component:  Compiler          |           Version:  8.0.1
           Keywords:                    |  Operating System:  MacOS X
       Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
          Test Case:                    |        Blocked By:
           Blocking:                    |   Related Tickets:
Differential Rev(s):                    |         Wiki Page:
----------------------------------------+---------------------------------
 Darwin did not support `clock_gettime` until Sierra, which added it.
 Unfortunately, the existing `MACOSX_DEPLOYMENT_TARGET` environment
 variable has no effect on its availability, so binary distributions
 compiled on Sierra will be incompatible with older releases.

 We have three options for dealing with this,
 1. Disable `clock_gettime` support in our OS X binary distributions (e.g.
 `./configure ac_cv_func_clock_gettime=no`)
 2. Produce one binary distribution for Sierra and another for previous
 releases
 3. Making it possible to change timer backends at runtime.

 At the moment I'm leaning towards (1). (2) is another possibility. (3)
 seems like a road to madness.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12858>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler