C/C++: don't suggest implementation names as spelling fixes (PR c/83236)

C/C++: don't suggest implementation names as spelling fixes (PR c/83236)

gcc/c-family/ChangeLog:
	PR c/83236
	* c-common.c (selftest::c_family_tests): Call
	selftest::c_spellcheck_cc_tests.
	* c-common.h (selftest::c_spellcheck_cc_tests): New decl.
	* c-spellcheck.cc: Include "selftest.h".
	(name_reserved_for_implementation_p): New function.
	(should_suggest_as_macro_p): New function.
	(find_closest_macro_cpp_cb): Move the check for NT_MACRO to
	should_suggest_as_macro_p and call it.
	(selftest::test_name_reserved_for_implementation_p): New function.
	(selftest::c_spellcheck_cc_tests): New function.
	* c-spellcheck.h (name_reserved_for_implementation_p): New decl.

gcc/c/ChangeLog:
	PR c/83236
	* c-decl.c (lookup_name_fuzzy): Don't suggest names that are
	reserved for use by the implementation.

gcc/cp/ChangeLog:
	PR c/83236
	* name-lookup.c (consider_binding_level): Don't suggest names that
	are reserved for use by the implementation.

gcc/testsuite/ChangeLog:
	PR c/83236
	* c-c++-common/spellcheck-reserved.c: New test case.

From-SVN: r255453