c.opt: Add -W(no-)overlength-strings.

gcc:
	* c.opt: Add -W(no-)overlength-strings.
	* doc/invoke.texi: Document it.
	* c-opts.c (c_common_handle_option): -pedantic implies
	-Woverlength-strings, if not explicitly disabled already.
	(c_common_post_options): -Woverlength-strings defaults to off, and
	is always off for C++.
	* c-common.c (fix_string_type): Issue warning about strings longer
	than is portable only if warn_overlength_strings.  Rearrange code
	a little for clarity.
	* configure.in: Check for -Wno-overlength-strings as well before
	enabling -pedantic in stage 1.
	* Makefile.in (STRICT2_WARN): Add -Wno-overlength-strings.
	(gcc.o-warn, insn-automata.o-warn, build/gencondmd.o-warn): Delete.

	* genconditions.c (write_header, write_one_condition)
	(write_conditions, write_writer): Consolidate very long strings
	that were broken up to fit in C89 portable limit.  Don't use
	printf when fputs will do.

gcc/testsuite:
	* gcc.dg/Woverlength-strings.c
	* gcc.dg/Woverlength-strings-pedantic-c89.c
	* gcc.dg/Woverlength-strings-pedantic-c89-no.c
	* gcc.dg/Woverlength-strings-pedantic-c99.c
	* gcc.dg/Woverlength-strings-pedantic-c99-no.c: New tests.

==================================================================

From-SVN: r110360