gcc/
	* Makefile.in (BUILD_RTL): Move build/read-md.o to...
	(BUILD_MD): ...this new variable.
	(simple_generated_rtl_h, simple_generated_rtl_c): New variables
	that include the old contents of simple_generated_h and
	simple_generated_c.
	(simple_generated_h, simple_generated_c): Include them.  Add
	insn-constants.h.
	(s-%): Make simple_generated_{h,c} stamps depend on $(MD_DEPS)
	and simple_generated_rtl_{h,c} stamps depend on insn-conditions.md.
	Remove these dependencies from the main rule and include
	insn-conditions.md in the command line only if it appears
	in the dependency list.
	(insn-constants.h, s-constants): Delete.
	(build/genconstants.o): Don't depend on $(RTL_BASE_H), $(GTM_H)
	or gensupport.h.
	(build/genmddeps.o): Likewise.
	(genprogrtl): New variable that contains everything from genprogmd
	except mddeps and constants.
	(genprogmd): Redefine in terms of genprogrtl.  Make these programs
	depend on $(BUILD_MD)
	(genprog): New variable.  Make these programs depend on
	$(BUILD_ERRORS).
	* genmddeps.c: Don't include tm.h, rtl.h or gensupport.h.
	(main): Use read_md_files instead of init_rtx_reader_args.
	* genconstants.c: As for genmddeps.c.
	* read-md.h (read_skip_construct): Declare.
	* read-md.c (read_skip_construct): New function.
	(handle_file): Allow a null handle_directive, skipping the
	construct if so.
	(parse_include): Update the comment accordingly.

From-SVN: r160578