c-family/
	* c-opts.c (c_common_post_options): Set warn_implicit_int.
	* c.opt (Wimplicit-int): Initialize to -1.
c/
	* c-decl.c (grokdeclarator): Use OPT_Wimplicit_int unconditionally.
	(start_function): Use OPT_Wimplicit_int instead of 0.
	(store_parm_decls_oldstyle): Likewise.
testsuite/
	* gcc.dg/Wimplicit-int-1.c: New test.
	* gcc.dg/Wimplicit-int-2.c: New test.
	* gcc.dg/Wimplicit-int-3.c: New test.
	* gcc.dg/Wimplicit-int-4.c: New test.

From-SVN: r216412