Original patch from Gentoo:
gentoo/src/patchsets/binutils/2.19/03_all_binutils-2.15.92.0.2-ppc64-pie.patch

diff -durN binutils-2.19.orig/bfd/elf64-ppc.c binutils-2.19/bfd/elf64-ppc.c
--- binutils-2.19.orig/bfd/elf64-ppc.c	2008-10-09 14:18:24.000000000 +0200
+++ binutils-2.19/bfd/elf64-ppc.c	2008-11-23 16:16:11.000000000 +0100
@@ -11294,7 +11294,12 @@
 	      else if (!SYMBOL_REFERENCES_LOCAL (info, &h->elf)
 		       && !is_opd
 		       && r_type != R_PPC64_TOC)
-		outrel.r_info = ELF64_R_INFO (h->elf.dynindx, r_type);
+		{
+		  outrel.r_info = ELF64_R_INFO (h->elf.dynindx, r_type);
+		  if (h->elf.dynindx == -1
+		      && h->elf.root.type == bfd_link_hash_undefweak)
+		  memset (&outrel, 0, sizeof outrel);
+		}
 	      else
 		{
 		  /* This symbol is local, or marked to become local,