As a prerequisite for being able to test an uninstalled libtoolize

As a prerequisite for being able to test an uninstalled libtoolize
for copying files correctly from the source tree, we must know
exactly which files should be copied by the --ltdl option to avoid
accidentally picking up compilation objects and other noise when
$builddir == $srcdir:

* libltdl/loaders/Makefile.am (ltdldatadir, ltdldatafiles)
(install-data-local): Removed...
* libltdl/Makefile.am (ltdldatafiles): ...and consolidated here.
(show-ltdldatafiles): New rule...
* Makefile.am (ltdldatafiles, libtoolize): ...used to substitute
exactly which files are installed by libtoolize --ltdl.
(edit): Move pkgvmacro_DATA substitution expression...
(libtoolize): ...to here.
* libtoolize.m4sh: Use func_copy_some_files() instead of
func_copy_all_from_path() to copy the --ltdl option installed
files.
(pkgvltdldirs): New path variable to search for	files installed by
--ltdl option.
(func_massage_pkgvltdl_files): New function to calculate the list
of ltdl installation files.