* configure.in: Require at least autoconf 2.3, because earlier versions lose on

* configure.in: Require at least autoconf 2.3, because earlier versions lose on
some AIX versions.
* configure: Regenerated.

* configure.in: Add m68k-*-elf.
* config/tc-m68k.c (comment_chars) [OBJ_ELF]: Include '#'.
(md_pseudo_table) [OBJ_ELF]: Ignore "swbeg".
(md_begin): Set alt_notend_table['&'], so svr4-style immediate operands are
accepted.
(md_apply_fix): Argument VALP should point to valueT.
(md_convert_frag): Argument SEC should be type segT.
(md_shortopts) [OBJ_ELF]: Accept 'Q' with an argument.
(md_parse_option): Ignore it.
(md_convert_frag_1): Add in frag address for the symbol in the displacement
calculation.
* config/tc-m68k.h (TARGET_FORMAT) [OBJ_ELF]: Use "elf32-m68k".
(TARGET_ARCH): Define.
(REGISTER_PREFIX_OPTIONAL) [OBJ_ELF]: Default to 0.
(LOCAL_LABEL, FAKE_LABEL_NAME, REGISTER_PREFIX_OPTIONAL): Handle these the same
way for OBJ_ELF as for M68KCOFF.