re PR other/1502 (Nonexistent -W options not diagnosed)

re PR other/1502 (Nonexistent -W options not diagnosed)

	PR other/1502:
	* cppinit.c (cpp_handle_option): Add ignore argument, if it is zero,
	don't ignore unrecognized -W* options.
	(cpp_handle_options): Pass 1 as last argument to cpp_handle_option.
	* cpplib.h (cpp_handle_option): Adjust prototype.
	* c-decl.c (c_decode_options): Pass 0 as last argument to
	cpp_handle_option.

	PR c/2896:
	* gcc.c (cpp_unique_options): Split from cpp_options.
	(cpp_options): Source cpp_unique_options.
	(default_compilers): Use cpp_unique_options instead of cpp_options
	when used together with cc1_options.
	(static_specs): Add cpp_unique_options.
	* objc/lang-specs.h: Use cpp_unique_options instead of cpp_options
	when used together with cc1_options.

	* decl2.c (cxx_decode_option): Pass 0 as last argument to
	cpp_handle_option.
	* lang-specs.h: Use cpp_unique_options instead of cpp_options
	when used together with cc1_options.

From-SVN: r49315