* aclocal.in (ac_defun_rx, ac_require_rx): If the macro name is
quoted, accept any character but `]'. This makes it possible
to define macros such as `AC_LANG_PREPROC(Fortran 90)'.
(scan_m4_files): Quote $key in the regex. Don't define $expr, it's
not used.
(add_file, scan_file): Adjust to the new definitions of $ac_defun_rx
and $ac_require_rx.
* tests/aclocal2.test: New file.
* tests/Makefile.am (TESTS): Add aclocal2.test.
Reported by Tamara L. Dahlgren and Tom Epperly.