Gnulib has changed again. Reimport. Adjust. Rinse. Repeat.

Gnulib has changed again.  Reimport.  Adjust.  Rinse.  Repeat.
Automake and Libtool now agree on subdir-objects and LTLIBOBJS,
and libtoolize does a better job of ltdl importing now too, so
take advantage of that while updating the tree:

* acm4, config: Moved from here...
* ltdl/m4, ltdl/config: ...to here.
* doc/Makefile.am, m4/Makefile.am, modules/Makefile.am,
src/Makefile.am, tests/Makefile.am: Removed...
* Makefile.am: ...and migrated to here, with adjustments to
compensate for relative path differences.
* commit: Adjust relative paths.
* configure.ac: Adjust relative paths.
(AC_PREREQ): 2.59 isn't strictly new enough, we also need a
patch.
(LT_PREREQ): 2.0 isn't released yet, but will work when it is!  In
the meanwhile, CVS HEAD libtool is needed.
(AM_INIT_AUTOMAKE): Added subdir-objects declaration. 1.9.5 isn't
stricly new enough, we also need a patch.
(AM_PROG_CC_C_O): Required for subdir-objects in Automake.
(AC_WITH_LTDL): Replaced with LT_WITH_LTDL.
(gl_MODULES): Don't list getopt and version-etc, as they don't
belong in libm4.
* bootstrap: After running gnulib-tool to import the listed
modules, fetch getopt and version-etc into src manually.
(ltdldir): Change to ltdl.
* src/main.c: Adjust for changes in version-etc API.
* ltdl/m4/m4-getopt.m4: New macro to mirror gnulib's getopt.m4,
but works when the getopt module isn't to be included in the lib.
* README: Add note about patching autoconf and automake to
bootstrap CVS m4.