grub-emu module load support.

	grub-emu module load support.

	* Makefile.in (TARGET_NO_MODULES): New variable. All users of
	NO_DYNAMIC_MODULES switched to this.
	(TARGET_CFLAGS): Add -DGRUB_TARGET_NO_MODULES=1 if applicable.
	(CFLAGS): Likewise.
	* conf/any-emu.rmk: Generate symlist.
	(kernel_img_HEADERS): Add util/datetime.h.
	(kernel_img_HEADERS) [sdl]: Add sdl.h.
	(kernel_img_HEADERS) [libusb]: Add libusb.h.
	(kernel_img_SOURCES) [TARGET_NO_MODULES = no && !x86]: Add
	kern/$(target_cpu)/cache.S.
	* configure.ac (grub-emu-modules): New option.
	* genmk.rb: Handle multiple source lists.
	* include/grub/sdl.h: New file.
	* include/grub/libusb.h: Likewise.
	* util/grub-emu.c (main): Hanle (host) root.
	* util/hostdisk.c (grub_util_biosdisk_get_grub_dev): Error with
	GRUB_ERR_UNKNOWN_DEVICE.
	* util/misc.c: Move mm functions to ...
	* util/mm.c: ... here. All users updated.