This patch fix VSCR position on ucontext. VSCR was read in the wrong
position on ucontext structure because it was ignoring the machine
endianess.
[BZ #24088]
* sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h (vscr_t): Added
ifdef to fix read of VSCR.
* sysdeps/powerpc/powerpc64/Makefile [$subdir == stdlib]: Add
tst-ucontext-ppc64-vscr.c to test list.
* sysdeps/powerpc/powerpc64/tst-ucontext-ppc64-vscr.c: New test file.
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>