* config.gcc: Support --with-cpu=ia.

	* config/i386/i386.c (cpu_names): Add "ia".
	(processor_alias_table): Likewise.
	(ix86_option_override_internal): Disallow -march=ia.
	* config/i386/i386.h (target_cpu_default): Add
	TARGET_CPU_DEFAULT_ia.

	* doc/invoke.texi: Document -mtune=ia.

From-SVN: r205719