driver-i386.c (host_detect_local_cpu): Add support for skylake.

driver-i386.c (host_detect_local_cpu): Add support for skylake.

gcc/

	* config/i386/driver-i386.c (host_detect_local_cpu): Add support
	for skylake.
	* config/i386/i386.c (PTA_SKYLAKE): New macros.
	(processor_alias_table): Add skylake description.
	(enum processor_model): Add skylake processor.
	(arch_names_table): Add skylake record.
	* doc/invoke.texi: Add skylake item.

gcc/testsuite/

	* gcc.target/i386/builtin_target.c: Add skylake check.

libgcc/

	* config/i386/cpuinfo.c (enum processor_subtypes): Add skylake.
	(get_intel_cpu): Likewise.

From-SVN: r226884