malloc: Fix MALLOC_DEBUG -Wundef warning

MALLOC_DEBUG is set optionally on the command line. Default the value
to zero if it is not set on the command line, and test its value
with #if rather than #ifdef. Verified the code is identical before
and after this change apart from line numbers.

ChangeLog:

2014-04-11  Will Newton  <will.newton@linaro.org>

	* malloc/malloc.c [!MALLOC_DEBUG]: #define MALLOC_DEBUG
	to zero if it is not defined elsewhere.  (mtrim): Test
	the value of MALLOC_DEBUG with #if rather than #ifdef.
Fix typo in comment in res_query.c
NEWS: Add comment about changed ABI on s390 and s390x.
S/390: Unify 31 and 64 bit configure.ac
Fixed and unified pthread_once.

[BZ #15215] This unifies various pthread_once architecture-specific
implementations which were using the same algorithm with slightly different
implementations.  It also adds missing memory barriers that are required for
correctness.
benchtests: Improve readability of JSON output

Add a small library to print JSON values and use it to improve the
readability of the benchmark output and the readability of the
benchmark code.

ChangeLog:

2014-04-11  Will Newton  <will.newton@linaro.org>

	* benchtests/Makefile (extra-objs): Add json-lib.o.
	(bench-func): Tidy up JSON output.
	* benchtests/bench-skeleton.c: Include json-lib.h.
	(main): Use JSON library functions to do output of
	benchmark results.
	* benchtests/bench-timing-type.c (main): Output the
	timing type simply, leaving formatting to the user.
	* benchtests/json-lib.c: New file.
	* benchtests/json-lib.h: Likewise.
2014-04-11  Paul Pluzhnikov  <ppluzhnikov@google.com>

	* elf/Makefile (tests): make tst-dlopen-aout conditional on
	enable-hardcoded-path-in-tests
math: make test-fenv-preserve.c a no-op if FE_ALL_EXCEPT == 0.

This fixes a testsuite failure for tile (and possibly microblaze).
Fix typo on ChangeLog.