libtool: fix running the unit-tests with spack install --test root (#25707)
libtool: fix running the unit-tests with spack install --test root (#25707)

Besides adding autoconf and automake as needed for tests of 2.4.6,
skip Fortran test cases when Fortran compilers are not provided.
LLNL/spack,LLNL/spack,LLNL/spack,LLNL/spack,LLNL/spack