Validate bench.out against a JSON schema

This patch adds a JSON schema for the benchmark output file and also
adds a script that validates the generated output against the schema.
PowerPC: Optimized strcmp for PPC64/POWER7

Optimization is achieved on 8 byte aligned strings with double word
comparison using cmpb instruction. On unaligned strings loop unrolling
is applied for Power7 gain.
AArch64: Define TLS_DEFINE_INIT_TP
PowerPC: Define TLS_DEFINE_INIT_TP
Alpha: Define TLS_DEFINE_INIT_TP
S390: Define TLS_DEFINE_INIT_TP
Tile: Define TLS_DEFINE_INIT_TP
tile: Consolidate NPTL/non versions of vfork
posix_spawn_file_actions_addopen needs to copy the path argument (BZ 17048)

POSIX requires that we make a copy, so we allocate a new string
and free it in posix_spawn_file_actions_destroy.

Reported by David Reid, Alex Gaynor, and Glyph Lefkowitz.  This bug
may have security implications.
conformtest: clean up POSIX expectations for sys/mman.h, sys/stat.h, sys/types.h.

Continuing the series of patches to clean up conformtest expectations
for "POSIX" (1995/6) based on review of the expectations against the
standard, this patch cleans up expectations for sys/mman.h, sys/stat.h
and sys/types.h.  Tested x86_64; no new XFAILs needed.

	* conform/data/sys/mman.h-data [POSIX] (size_t): Do not require
	type.
	[POSIX] (off_t): Likewise.
	* conform/data/sys/stat.h-data (S_IRGRP): Require constant.
	[POSIX] (S_ISBLK): Require macro.
	[POSIX] (S_ISCHR): Likewise.
	[POSIX] (S_ISDIR): Likewise.
	[POSIX] (S_ISFIFO): Likewise.
	[POSIX] (S_ISREG): Likewise.
	[POSIX || XPG3 || XPG4 || UNIX98] (S_TYPEISTMO): Do not list
	optional-macro.
	* conform/data/sys/types.h-data [POSIX] (blkcnt_t): Do not require
	type.
	[POSIX] (time_t): Likewise.
	[POSIX] (timer_t): Likewise.