re PR c++/77948 (Option processing of -std=c++11 -std=gnu++11 doesn't reset ext_numer...

re PR c++/77948 (Option processing of -std=c++11 -std=gnu++11 doesn't reset ext_numeric_literals)

	PR c++/77948
	* c.opt (fext-numeric-literals): Add Var and Init.
	* c-opts.c (c_common_handle_option): Don't clear
	cpp_opts->ext_numeric_literals for -std=c++{11,14,1z}.
	(c_common_post_options): Clear it here if not set
	explicitly.

	* g++.dg/cpp0x/pr77948-1.C: New test.
	* g++.dg/cpp0x/pr77948-2.C: New test.
	* g++.dg/cpp0x/pr77948-3.C: New test.
	* g++.dg/cpp0x/pr77948-4.C: New test.
	* g++.dg/cpp0x/pr77948-5.C: New test.
	* g++.dg/cpp0x/pr77948-6.C: New test.

From-SVN: r241707