libc/uClibc: fix building on system with recent glibc

While trying to build a toolchain with ct-ng 1.5.0,
arm-unknown-linux-uclibcgnueabi target,
I get the following error:

[INFO ] Installing C library headers
[EXTRA] Copying sources to build dir
[EXTRA] Applying configuration
[EXTRA] Building headers
[EXTRA] Installing headers
[ERROR] extra/scripts/unifdef.c:209: error: conflicting types for 'getline'
[ERROR] make[2]: *** [extra/scripts/unifdef] Error 1
[ERROR] Build failed in step 'Installing C library headers'

The following patch solves the problem.
(It's a backport of this uClibc commit:
http://git.uclibc.org/uClibc/commit/?id=49e81cada73616864b9b31df0aeb6961c30f5a6e
)

[--SNIP from another mail--]
AFAIK this is a problem since glibc 2.10.
(transplanted from 1ba79f2126df8bd89120899a58f2d0bcc2e9c771)

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,