gcc-dg.exp (gcc-dg-prune): Make linker message check less strict so it also works...

gcc-dg.exp (gcc-dg-prune): Make linker message check less strict so it also works with auto-overlay support.

	* lib/gcc-dg.exp (gcc-dg-prune): Make linker message check
	less strict so it also works with auto-overlay support.
	* lib/gcc-defs.exp (${tool}_check_unsupported_p): Add check
	for "exceeds local store" linker errors on the SPU.

	* lib/gfortran.exp: Include target-supports.exp.
	(gfortran_init): On SPU targets where automatic overlay support
	is available, use it to build all Fortran test cases.

	* gfortran.dg/pr20257.f90: Skip on spu-*-* targets.

From-SVN: r146242