ENABLE_CHECKING refactoring: C family front ends

ENABLE_CHECKING refactoring: C family front ends

gcc/c-family/

	* c-omp.c (c_omp_split_clauses): Remove conditional compilation. Use
	flag_checking.

gcc/cp/

	* call.c (validate_conversion_obstack): Define unconditionally.
	* constexpr.c (maybe_constant_value, fold_non_dependent_expr): Use
	gcc_checking_assert.
	* cp-tree.h: Use CHECKING_P instead of ENABLE_CHECKING.
	* decl2.c (cxx_post_compilation_parsing_cleanups): Use flag_checking.
	* mangle.c (add_substitution): Likewise.
	* method.c (maybe_explain_implicit_delete): Likewise.
	* parser.c (cp_parser_template_argument_list): Remove conditional
	compilation.
	* pt.c (check_unstripped_args): Rename to...
	(verify_unstripped_args): ... this and remove conditional compilation.
	(retrieve_specialization): Guard call of verify_unstripped_args with
	flag_checking.
	(template_parm_to_arg): Remove conditional compilation.
	(template_parms_to_args, coerce_template_parameter_pack,
	coerce_template_parms): Likewise.
	(tsubst_copy): Use flag_checking.
	(type_unification_real): Remove conditional compilation.
	(build_non_dependent_expr): Use flag_checking.
	* tree.c (build_target_expr): Remove conditional compilation, use
	gcc_checking_assert.
	* typeck.c (comptypes): Likewise.
	* typeck2.c (digest_init_r): Likewise.

From-SVN: r229756