STT_GNU_IFUNC

[David Miller]

This change:

commit 0feab8d4ed9ead53886039a92f1b53d9408371d3
Author: Ulrich Drepper <drepper@redhat.com>
Date:   Thu Mar 12 06:31:10 2009 +0000

    (elf_machine_rela): Add branch prediction.  A few size optimizations.

Adds STT_GNU_IFUNC:

+      if (sym != NULL
+	  && __builtin_expect (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC,
+			       0))
+	value = ((Elf64_Addr (*) (void)) value) ();
+

although this isn't described in the changelog and no definition
for STT_GNU_IFUNC was added to elf/elf.h, so I doubt this even
builds.