[PATCH v2 1/9] Add configure check to test if gcc supports attribute ifunc.

[Paul E. Murphy]

On 08/08/2016 09:38 AM, Stefan Liebler wrote:
> This patch adds a configure check to test if gcc supports attribute ifunc.
> The support can either be enabled in <gcc-src>/gcc/config.gcc for one
> architecture in general by setting default_gnu_indirect_function variable to yes
> or by configuring gcc with --enable-gnu-indirect-function.
> 
> The next patch rewrites libc_ifunc macro to use gcc attribute ifunc instead
> of inline assembly to generate the IFUNC symbols due to false debuginfo.
> 
> If gcc does not support attribute ifunc and glibc is configured with
> --enable-multi-arch then configure will abort with an error message.
> If --enable-multi-arch is not given then configure will silently
> disable multi-arch support.
> 
> ChangeLog:
> 
> 	* configure.ac: Add check if gcc supports attribute ifunc feature.
> 	* configure: Regenerated.


One more hiccup after trying out this patch.  pt-vfork.c mandates ifunc
on most (all?) targets using nptl.  It seems configure needs to mandate
this support on any target using nptl.