[Bug libgcc/78064] unwind-c.c never uses _Unwind_GetIPInfo

[wilson at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78064

Jim Wilson <wilson at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |wilson at gcc dot gnu.org

--- Comment #1 from Jim Wilson <wilson at gcc dot gnu.org> ---
I tracked the problem down to bug 27880 comment 31.
    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27880#c31
The patch is arguably correct, but it changes config.in from
#undef HAVE_GETIPINFO
to
#ifndef USED_FOR_TARGET
#undef HAVE_GETIPINFO    #undef HAVE_GETIPINFO
#endif
config.in is used to generate auto-host.h, which is included by unwind-c.c. 
But the new ifndef prevents HAVE_GETIPINFO from being defined in unwind-c.c, as
USED_FOR_TARGET is defined in tconfig.h before auto-host.h is included.

Now that we have an auto-target.h file in libgcc, we can fix the problem by
including that.

This was OK in gcc-4.3, and broken in gcc-4.4 and later.  The libgcc
auto-target.h file appeared in gcc-4.8.  So fixing gcc-4.4 to gcc-4.7 looks a
bit complicated, but anything gcc-4.8 and later looks easy to fix.  We of
course only care about gcc 5 and later at this point.