re PR other/12081 (Gcc can't be compiled with -mregparm=3)

	PR other/12081
	* recog.h (rtx (*insn_gen_fn) (rtx, ...)): Replace typedef with	new
	class insn_gen_fn.
	* expr.c (move_by_pieces_1, store_by_pieces_2): Replace argument
	rtx (*) (rtx, ...) with insn_gen_fn.
	* genoutput.c (output_insn_data): Cast gen_? function pointers to
	insn_gen_fn::stored_funcptr.  Add initializer braces.

From-SVN: r201513