invoke.texi (floop-flatten): Declare obsolete.

invoke.texi (floop-flatten): Declare obsolete.

	gcc/
	* doc/invoke.texi (floop-flatten): Declare obsolete.
	* toplev.c (process_options): Remove references to flag_loop_flatten.
	* tree-ssa-loop.c (gate_graphite_transform): Same.
	* common.opt (floop-flatten): Obsolete.
	* graphite-poly.c (apply_poly_transforms): Remove reference to
	flag_loop_flatten.
	* Makefile.in (graphite-flattening.o): Remove.
	* graphite-flattening.c: Remove.

	gcc/testsuite/
	* gcc.dg/graphite/pr50561.c: Update.

From-SVN: r184820