[MacPorts] #57130: clang-7.0: build fails in compiler-rt/lib/xray on darwin < 15 due to several issues

[MacPorts]

#57130: clang-7.0: build fails in compiler-rt/lib/xray on darwin < 15 due to
several issues
--------------------+-----------------------
 Reporter:  kencu   |      Owner:  jeremyhu
     Type:  defect  |     Status:  assigned
 Priority:  Normal  |  Milestone:
Component:  ports   |    Version:
 Keywords:          |       Port:  clang-5.0
--------------------+-----------------------
 there are three issues building XRAY on older systems (that I have found
 so far).

 1. It needs thread local storage, which results in systems < darwin 11
 failing.
 2. MAP_ANONYMOUS is used but undefined on older systems. This is fixed
 easily enough by replacing the definition with -DMAP_ANONYMOUS=MAP_ANON. I
 did it by adding the definition in compiler-rt/CMakeLists.txt to cover all
 the instances at once.
 3. error: use of undeclared identifier 'CLOCK_REALTIME'. This one may be
 harder to fix. There are some example replacement functions
 <https://stackoverflow.com/questions/5167269/clock-gettime-alternative-in-
 mac-os-x> but I'm not sure if any of them truly offer a suitable
 replacement.

 These issues may result in XRAY being disabled on all the non-building
 systems (currently darwin < 15).

 When XRAY is disabled on darwin10 clang-7.0 builds through to completion
 (this fix is already in the Portfile restricted to darwin 10 or less
 <https://github.com/macports/macports-
 ports/commit/3f03093e264ea484508dbbcc6f8cbc14b18a23df> ).

-- 
Ticket URL: <https://trac.macports.org/ticket/57130>
MacPorts <https://www.macports.org/>
Ports system for macOS