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)

diff -durN glibc-2.6.1.orig/glibc-ports-2.6.1/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h glibc-2.6.1/glibc-ports-2.6.1/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h

--- glibc-2.6.1.orig/glibc-ports-2.6.1/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h	2005-11-16 20:22:59.000000000 +0100

+++ glibc-2.6.1/glibc-ports-2.6.1/sysdeps/unix/sysv/linux/arm/nptl/sysdep-cancel.h	2007-09-06 13:53:16.000000000 +0200

@@ -126,3 +126,9 @@

 # define NO_CANCELLATION 1

 #endif

+

+#ifndef __ASSEMBLER__

+# define RTLD_SINGLE_THREAD_P \

+  __builtin_expect (THREAD_GETMEM (THREAD_SELF, \

+                   header.multiple_threads) == 0, 1)

+#endif