* tta/perl/Texinfo/ModulePath.pm.in ($XS_modules_dir, init),
tta/perl/Texinfo/XSLoader.pm (init): set $XS_modules_dir in ModulePath
instead of prepending to @INC.  Search for libtool archive in
$XS_modules_dir only in XSLoader init.  Remove _find_file_in_inc.