* automake.in ($libtool_new_api): New variable. (handle_libtool): Do not libtool's aux files if $libtool_new_api. (scan_autoconf_traces) <LT_SUPPORTED_TAG>: Set $libtool_new_api. (scan_autoconf_traces) <AC_REQUIRE_AUX_FILE>: Remember only the first location for required files.