I'm at a loss. I have libtool-2.4 installed in /usr/local and I get this
error when 'make'ing after running

    ../configure --prefix=/usr/local --libdir=/usr/local/lib \
        --with-libreadline-prefix=/usr/local

[.... making lots of stuff ...]

  CCLD     libguile-2.0.la
../libtool: line 5989: cd: (libdir): No such file or directory
libtool: link: cannot determine absolute directory name of `(libdir)'
make[3]: *** [libguile-2.0.la] Error 1
make[3]: Leaving directory
`/home/ian/Documents/FP/guile-2.0.11/build/libguile'
make[2]: *** [all] Error 2

Another minor issue is that the configure script seems not to know about
the readline-6.3 which I have installed in /usr/local:

checking for rl_get_keymap... no
checking for rl_getc_function pointer in readline... no
configure: WARNING: *** GNU Readline is too old on your system.
configure: WARNING: *** You need readline version 2.1 or later.