[MacPorts] #44596: gmp @6.0.0_0: Autotools incorrectly selects "-undefined suppress" symbol lookup on Yosemite (was: libgcc @4.9.1_0, libgcc-devel @4.10-20140810: Build fails with internal compiler error)

[MacPorts]

#44596: gmp @6.0.0_0: Autotools incorrectly selects "-undefined suppress" symbol
lookup on Yosemite
------------------------+----------------------
  Reporter:  wichert@…  |      Owner:  larryv@…
      Type:  defect     |     Status:  assigned
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:
Resolution:             |   Keywords:  yosemite
      Port:  gmp        |
------------------------+----------------------
Changes (by larryv@…):

 * cc: mcalhoun@… (added)
 * version:  2.3.1 =>
 * port:  libgcc libgcc-devel => gmp


Comment:

 The GCC ICE was a red herring. You’ll be unsurprised to hear that this is
 Autotools’ fault.

 1. We set the `MACOSX_DEPLOYMENT_TARGET` environment variable to “10.10”.
 (Homebrew doesn’t set it at all and thus doesn’t start down this road to
 perdition.)
 2. Libtool (and, by extension, `configure` scripts built with it)
 interprets “10.10” as “10.1*”.
 3. OS X did not support dynamic lookup of undefined symbols until 10.3.
 Since Libtool thinks 10.10 Yosemite is 10.1 Puma, it tells the linker to
 ignore undefined symbols.
    {{{
 case ${MACOSX_DEPLOYMENT_TARGET-10.0},$host in
     10.0,*86*-darwin8*|10.0,*-darwin[[91]]*)
         _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
     10.[[012]]*)
         _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined
 ${wl}suppress' ;;
     10.*)
         _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
 esac
    }}}
 4. GMP binaries contain several unresolved symbols that it no doubt
 expects `dyld(1)` to look up later.
 5. Thanks to Libtool, `dyld(1)` has no such plans. It makes this very
 clear during GMP’s test suite.
    {{{
 Crashed Thread:        0  Dispatch queue: com.apple.main-thread

 Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
 Exception Codes:       EXC_I386_GPFLT

 Error Formulating Crash Report:
 Failed to read dyld_all_image_infos: Coudln't get the data

 Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
 0   libdyld.dylib                       0x7fff88c64432
 stack_not_16_byte_aligned_error + 0
    }}}
 6. This filters up to anything trying to use GMP. Like, say, GCC trying to
 optimize some code.

 Marcus, I’m attaching my fix; may I commit it? (I bumped the revision
 because this problem only manifests at runtime.)

-- 
Ticket URL: <https://trac.macports.org/ticket/44596#comment:35>
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