* config/mips/driver-native.c [__sgi__]: Include <invent.h>,
	<sys/sbd.h>.
	(cpu_types): New array.
	(cputype): New function.
	(host_detect_local_cpu): Only define buf, f if !__sgi__.
	Use scaninvent instead of /proc/cpuinfo if __sgi__.
	* config.host: Also use driver-native.o, mips/x-native on
	mips-sgi-irix*.
	* config/mips/iris6.h [__mips__] (host_detect_local_cpu):
	Declare.
	(EXTRA_SPEC_FUNCTIONS, MARCH_MTUNE_NATIVE_SPECS): Define.
	(DRIVER_SELF_SPECS): Add MARCH_MTUNE_NATIVE_SPECS.

From-SVN: r176947