Also test -std=c++0x mode with 'make check-c++' at top level

Also test -std=c++0x mode with 'make check-c++' at top level
	* Makefile.in (check-gcc-c++0x): New.
	(check-c++): Depend on it.
gcc/
	* Makefile.in ($(lang_checks_parallelized)): Allow --tool_opts.
gcc/cp/
	* Make-lang.in (check-c++0x): New.
gcc/testsuite/
	* lib/g++.exp (${tool}_option_help, ${tool}_option_proc): Remove.
	* lib/lto.exp (lto_prune_warns): Prune warning about -std=c++0x
	when compiling C files.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@176250 138bc75d-0d04-0410-961f-82ee72b054a4