PR testsuite/57605
libstdc++-v3/
	* testsuite/lib/libstdc++.exp (libstdc++_init): Prepend
	-fdiagnostics-color=never to cxxflags.
libmudflap/
	* testsuite/lib/libmudflap.exp (libmudflap-init): Append
	-fdiagnostics-color=never to cxxflags.
libgomp/
	* testsuite/lib/libgomp.exp: Add -fdiagnostics-color=never to
	ALWAYS_CFLAGS.

From-SVN: r202791