I'm trying to build libtool-2.4.6 on an Apple M1. Configure dies at:

configure:3902: checking whether the C compiler works
configure:3924: /Library/Developer/CommandLineTools/usr/bin/clang
-fno-common -I/usr/local/include -DNDEBUG -L/usr/local/lib conftest.c
>&5
ld: library not found for -lSystem

I think that means it is time to update libtool (and its
dependencies), and release a new tarball.

Thanks.