PR target/50694
	* config/sh/sh.h (IS_LITTLE_ENDIAN_OPTION, UNSUPPORTED_SH2A):
	New macros.
	(DRIVER_SELF_SPECS): Use new macros to filter out
	unsupported options taking the default configuration into
	account.
	* gcc.target/sh/pr21255-2-ml.c: Skip if -mb or -m5* is
	specified.  Remove redundant runtime checks.
	* gcc.target/sh/20080410-1.c: Skip if -mb is specified.
	Allow for other than -m4.  Fix typos in comments.

From-SVN: r181340