c.opt (Wterminate): New.

c.opt (Wterminate): New.

gcc/c-family/
	* c.opt (Wterminate): New.
gcc/cp/
	* cp-gimplify.c (cp_genericize_r): Track TRY_BLOCK and
	MUST_NOT_THROW_EXPR, warn about a THROW_EXPR directly within a
	MUST_NOT_THROW_EXPR.
	(cp_genericize_data): Add try_block field.
	(cp_genericize_tree): Initialize it.
	* except.c (expand_end_catch_block): Set TREE_NO_WARNING on
	implicit rethrow.

From-SVN: r222842