Split config.h for util and core.

	Split config.h for util and core.

	* acinclude.m4 (HAVE_ASM_USCORE): Transformed into a variable.
	(ADDR32): Likewise.
	(DATA32): Likewise.
	(BSS_START_SYMBOL): Likewise.
	(END_SYMBOL): Likewise.
	(NEED_ENABLE_EXECUTE_STACK): Likewise. All users updated.
	(grub_I386_ASM_ABSOLUTE_WITHOUT_ASTERISK): Removed.
	* config.h.in: New file.
	* configure.ac: Use config-util.h as config define file.
	Rename MACHINE into GRUB_MACHINE. All users updated.
	(NEED_REGISTER_FRAME_INFO): Transformed into a variable. All users
	updated.
	(NESTED_FUNC_ATTR): Likewise.
	Substitue new variables.
	(COND_HAVE_ASM_USCORE): New conditional.
	* grub-core/Makefile.am (ASM_PREFIX): New variable.
	(kernel_syms.lst): Use ASM_PREFIX.
	* grub-core/kern/emu/console.c: Include config-util.h.
	* grub-core/kern/emu/misc.c: Likewise.
	* grub-core/kern/emu/mm.c: Likewise.
	* include/grub/emu/misc.h: Likewise.
	* include/grub/libgcc.h: Likewise.