ENABLE_CHECKING refactoring: remove remaining occurrences

libcpp/

	* config.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Remove ENABLE_CHECKING.

gcc/

	* cfganal.c (inverted_post_order_compute): Remove conditional
	compilation, use flag_checking.
	* config.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Remove ENABLE_CHECKING.
	* genconditions.c: Do not #undef ENABLE_CHECKING.
	* sese.h (bb_in_region): Comment out broken check.
	* tree-ssa-loop-manip.c (rewrite_into_loop_closed_ssa_1): Remove
	conditional compilation, use flag_checking.

From-SVN: r229758