bootstrap: properly check for libtool Commit 767ccd40 changed things to invoke libtoolize before gnulib-tool, but only for projects that use LT_INIT, even though we had already probed for libtool via older spellings. * build-aux/bootstrap (libtoolize): Also run libtool when older usage is detected. Signed-off-by: Eric Blake <eblake@redhat.com>