* c-common.c (c_common_init): Override cpplib's default
	warn_long_long setting.
	* c-lex.c (lex_number): Replace with interpret_integer,
	interpret_float, narrowest_unsigned_type and
	narrowest_signed_type, taking advantage of the new
	cpplib functionality.
	* cpperror.c (_cpp_begin_message): If a warning is turned
	into an error, avoid printing "warning:".
	* cppexp.c (cpp_num_sign_extend): New.
	* cppinit.c: Update comment.
	* cpplib.h (cpp_num_sign_extend): New.
	* tree.h: Update comment.
testsuite:
	* gcc.dg/wtr-int-type-1.c, gcc.dg/wtr-suffix-1.c,
	gcc.dg/cpp/paste4.c, gcc.dg/cpp/sysmac2.c:
	Update for mofified diagnostics.
	* gcc.dg/c99-intconst-1.c: No longer fail.

From-SVN: r54180