* config.gcc (powerpc*-*-* | rs6000-*-*): Add
	rs6000/option-defaults.h to tm_file.  Support cpu_32, cpu_64,
	tune_32 and tune_64.
	* doc/install.texi (--with-cpu-32, --with-cpu-64): Document
	support on PowerPC.
	* config/rs6000/rs6000.h (OPTION_DEFAULT_SPECS): Move to ...
	* config/rs6000/option-defaults.h: ... here.  New file.
	(OPT_64, OPT_32): Define.
	(MASK_64BIT): Define to 0 if not already defined.
	(OPT_ARCH64, OPT_ARCH32): Define.
	(OPTION_DEFAULT_SPECS): Add entries for cpu_32, cpu_64, tune_32
	and tune_64.

From-SVN: r146908