powerpc: Fix __arch_compare_and_exchange_bool_64_rel

Fix a typo in the inline assembly.
Fix warning in posix/bug-regex31.c.

This patch fixes a "set but not used" warning in posix/bug-regex31.c.
A variable res stored an indication of whether the test behaved as
expected, but was then ignored and the test returned 0 unconditionally
(as an mtrace test, the auxiliary test for leaks could still have
failed if that bug was present).  This patch makes the test return
res.

Tested for x86_64.

	* posix/bug-regex31.c (main): Return RES not 0.
fnmatch: work around GCC compiler warning bug with uninit var

* posix/fnmatch_loop.c (FCT): Use a scalar not a one-item array.
This works around a bug with x86-64 GCC 4.9.2 and earlier
where 'gcc -O2 -Wmaybe-uninitialized' incorrectly complains
"../locale/weightwc.h:93:7: warning: '*((void *)&str+4)' may be
used uninitialized in this function [-Wmaybe-uninitialized]".
Fix warning in stdio-common/tst-printf-round.c.

This patch fixes warnings of the form "tst-printf-round.c:202:17:
warning: passing argument 3 of 'test_hex_in_one_mode' discards 'const'
qualifier from pointer target type", by adding an extra const to that
argument (so that after array-to-pointer conversion it's const char
*const *).

Tested for x86_64.

	* stdio-common/tst-printf-round.c (test_hex_in_one_mode): Make
	third argument const.
Fix warning in setjmp/jmpbug.c.

This patch fixes a "set but not used" warning in setjmp/jmpbug.c.  A
variable is used only to store the result of alloca.  A cast to void
is added to avoid the warning, and the variable is made volatile to
ensure the call to alloca isn't optimized away for being unused.

Tested for x86_64.

	* setjmp/jmpbug.c (test): Make foo volatile and cast it to
	void.