Support on-demand global register allocation from

	Support on-demand global register allocation from
	R_MMIX_BASE_PLUS_OFFSET relocs.
	* emultempl/mmix-elfnmmo.em (mmix_after_allocation): Rename from
	mmix_set_reg_section_vma.  Call
	_bfd_mmix_finalize_linker_allocated_gregs.
	(mmix_before_allocation): New function.
	(LDEMUL_AFTER_ALLOCATION): Set to mmix_after_allocation.
	(LDEMUL_BEFORE_ALLOCATION): Define to mmix_before_allocation.
	* scripttempl/mmo.sc (.text): Mark .init, .fini as KEEP.
	(.MMIX.reg_contents): Add .MMIX.reg_contents.linker_allocated
	before .MMIX.reg_contents.
	* emultempl/mmo.em (gldmmo_before_allocation): Define to default.
	(mmo_after_open): New function.
	(LDEMUL_AFTER_OPEN): Define to mmo_after_open.
	* emulparams/elf64mmix.sh (OTHER_SECTIONS): Tweak formatting.  Add
	.MMIX.reg_contents.linker_allocated before .MMIX.reg_contents.