re PR c++/50920 (add a -std=c++11 option to the driver)

re PR c++/50920 (add a -std=c++11 option to the driver)

	PR c++/50920
gcc/c-family
	* c-common.h (cxx_dialect): Add cxx11 and cxx03.
	* c.opt: Add -std=c++11, -std=gnu++11, -std=gnu++03,
	and -Wc++11-compat.
	* c-opts.c (set_std_cxx11): Rename from set_std_cxx0x.
gcc/cp
	* class.c (check_field_decl): Change c++0x in diags to c++11.
	* error.c (maybe_warn_cpp0x): Likewise.
	* parser.c (cp_parser_diagnose_invalid_type_name): Likewise.
	* pt.c (check_default_tmpl_args): Likewise.
libcpp
	* include/cpplib.h (enum c_lang): Rename CLK_CXX0X to CLK_CXX11,
	CLK_GNUCXX0X to CLK_GNUCXX11.
libstdc++-v3
	* include/bits/c++0x_warning.h: Change -std=c++0x to -std=c++11.

From-SVN: r180707