PR ld/12815

	PR ld/12815
	* elf64-mmix.c (struct _mmix_elf_section_data): New members
	has_warned_bpo and has_warned_pushj.
	(mmix_final_link_relocate): Remove PARAMS and PTR macros,
	converting to ISO C.  Add new parameter error_message.  All
	callers changed.
	(mmix_elf_perform_relocation): Ditto.
	<case R_MMIX_PUSHJ_STUBBABLE, case R_MMIX_BASE_PLUS_OFFSET>:
	Handle the case where mmix_elf_check_common_relocs has not been
	called, missing preparations for relocs of the respective type.