PR c/51849
gcc/
	* gcc/doc/invoke.texi: Document -Wc90-c99-compat.
gcc/c-family/
	* c-opts.c (sanitize_cpp_opts): Pass warn_c90_c99_compat to libcpp.
	* c.opt (Wc90-c99-compat): Add option.
gcc/c/
	* c-decl.c (build_array_declarator): Remove check for !flag_isoc99.
	Call pedwarn_c90 instead of pedwarn.
	(check_bitfield_type_and_width): Likewise.
	(declspecs_add_qual): Likewise.
	(declspecs_add_type): Likewise.
	(warn_variable_length_array): Unify function for -pedantic and -Wvla.
	Adjust to only call pedwarn_c90.
	(grokdeclarator): Remove pedantic && !flag_isoc99 check.  Call
	pedwarn_c90 instead of pedwarn.
	* c-errors.c (pedwarn_c90): Handle -Wc90-c99-compat.
	* c-parser.c (disable_extension_diagnostics): Handle
	warn_c90_c99_compat.
	(restore_extension_diagnostics): Likewise.
	(c_parser_enum_specifier): Remove check for !flag_isoc99.  Call
	pedwarn_c90 instead of pedwarn.
	(c_parser_initelt): Likewise.
	(c_parser_postfix_expression): Likewise.
	(c_parser_postfix_expression_after_paren_type): Likewise.
	(c_parser_compound_statement_nostart): Remove check for !flag_isoc99.
	* c-tree.h: Fix formatting.
	* c-typeck.c (build_array_ref): Remove check for !flag_isoc99.  Call
	pedwarn_c90 instead of pedwarn.
gcc/testsuite/
	* gcc.dg/Wc90-c99-compat-1.c: New test.
	* gcc.dg/Wc90-c99-compat-2.c: New test.
	* gcc.dg/Wc90-c99-compat-3.c: New test.
	* gcc.dg/Wc90-c99-compat-4.c: New test.
	* gcc.dg/Wc90-c99-compat-5.c: New test.
	* gcc.dg/Wc90-c99-compat-6.c: New test.
	* gcc.dg/wvla-1.c: Adjust dg-warning.
	* gcc.dg/wvla-2.c: Adjust dg-warning.
	* gcc.dg/wvla-4.c: Adjust dg-warning.
	* gcc.dg/wvla-6.c: Adjust dg-warning.
libcpp/
	* lex.c (_cpp_lex_direct): Warn when -Wc90-c99-compat is in effect.
	* charset.c (_cpp_valid_ucn): Likewise.
	* include/cpplib.h (cpp_options): Add cpp_warn_c90_c99_compat.
	* macro.c (replace_args): Warn when -Wc90-c99-compat is in effect.
	(parse_params): Likewise.

From-SVN: r213786