Switch to libtool 2.4.7. * m4/libtool.m4: Update from libtool-2.4.7, with modifications: 2008-04-06 Bruno Haible <bruno@clisp.org> * m4/libtool.m4 (LT_INIT): When setting LIBTOOL, use CONFIG_SHELL; don't assume that the Makefile.in will set SHELL to ${CONFIG_SHELL}. * m4/ltoptions.m4: Likewise. * m4/ltsugar.m4: Likewise. * m4/ltversion.m4: Likewise. * m4/lt~obsolete.m4: Likewise. * build-aux/ltmain.sh: Update from libtool-2.4.7, with modifications: 2017-07-15 Bruno Haible <bruno@clisp.org> Allow building statically linked binaries, through LDFLAGS="-static". Apply patch from <https://lists.gnu.org/archive/html/bug-libtool/2017-07/msg00000.html>. * build-aux/ltmain.sh (func_mode_help, func_mode_link): In the link mode, accept option '-static-uninstalled-libs' in place of '-static', and make '-static' an equivalent of '-all-static'.