Re: problems with gnat on yosemite macox

[Simon Wright <simon@pushface.org>]

Leo Brewin <leo.brewin@internode.on.net> writes:

> Simon's gcc-4.8.0 binaries yield a small improvement but they too fail
> on a simple Hello World code,
>
>    which gnatmake
>    /opt/gcc-4.8.0/bin/gnatmake
>    
>    gnatmake lcb01.adb
>    gnatbind -x lcb01.ali
>    gnatlink lcb01.ali
>    gcc: warning: couldn't understand kern.osversion '14.0.0
>    gcc: warning: couldn't understand kern.osversion '14.0.0
>    Undefined symbols for architecture x86_64:
>      "__Unwind_Backtrace", referenced from:
>          ___gnat_backtrace in libgnat.a(tracebak.o)
>    	... similar lines deleted ...
>    ld: symbol(s) not found for architecture x86_64
>    collect2: error: ld returned 1 exit status
>    gnatlink: error when calling /opt/gcc-4.8.0/bin/gcc
>    gnatmake: *** link failed.

4.9.1 has the same problem.

The "couldn't understand kern.osversion" is related to GCC PR/61407;
apparently the pre-Yosemite version of this interface produced something
like "13.4" but Yosemite produces "14.0.0". I will see if I can backport
the relevant patch (SVN revision 215690, it looks like).

__Unwind_Backtrace (& friends, I expect) are provided by
libgcc_s.1.dylib, which is required by libgcc_ext.10.{4,5}.dylib.

The Mavericks link of hello.adb includes

   -macosx_version_min 10.9.4 
   [...]
   -no_compact_unwind 
   -lSystem 
   -lgcc_ext.10.5 
   -lgcc 
   -lSystem

The Yosemite link includes

   -macosx_version_min 10.4 
   [...]
   -lgcc_ext.10.4 
   -lgcc 
   -lSystem

and I think this is the cause of our problems.