libtoolize: massage installed libltdl file list at make time.

libtoolize: massage installed libltdl file list at make time.

* libtoolize.m4sh (pkgltdldir, pkgdatadir): Put installable
libltdl files in pkgdatadir. When testing, and _lt_pkgdatadir
is set, adjust to look in libltdl subdirectory.
(func_massage_pkgltdl_files): Removed function and only caller,
because...
(pkgltdl_files): ...we substitute the pre-massaged files
directly...
(func_install_pkgltdl_files): ...from here.
Adjust installation of specially handled additional files.
* Makefile.am (ltdldir): Location of libltdl files in source
tree.
(ltdldest, ltdldatafiles): Removed.
(pkgltdl_files): New pre-massaged list of libltdl sources.
(install-data-local, uninstall-hook): Use it.
* tests/libtoolize.at: Reorder expected output to match actual
libtoolize output.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>