[GHC] #15404: ghc-8.6 uninstallable on macos due to hard coded libgmp directory

[GHC]

#15404: ghc-8.6 uninstallable on macos due to hard coded libgmp directory
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        Reporter:  tmcdonell         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.6.2
       Component:  None              |              Version:
      Resolution:                    |             Keywords:
Operating System:  MacOS X           |         Architecture:
 Type of failure:  Installing GHC    |  Unknown/Multiple
  failed                             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by berdario):

 * milestone:  8.6.3 => 8.6.2


Comment:

 Thanks to dminuoso, he pointed out that the flag is actually defined for
 the inner library, and in fact should be toggled differently in the
 build.mk

 While running tests with this fix in
 https://github.com/ghc/ghc/pull/222/files this surfaced test failures due
 to https://ghc.haskell.org/trac/ghc/ticket/15105

 This turned out to be the same behavior in GHC 8.4, unclear why the
 failures weren't seen before. The .o code for the HSinteger-gmp-1.0.2.0.o
 had the same symbol table. The bug turned out to be in GHC static linker.
 We added a bunch more logging statements to the code that reads MachO
 symbols. It turned out that it was counting the number of external symbols
 (let's say M), and then going through the first M such symbols in the
 table (thus ignoring the last N-M symbols).

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15404#comment:12>
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