but forget to include --with-gdbm, then apr gets built in a way that
requires apr_gdbm, but doesn't build apr_gdbm. The result is that code
that tries to use apr_dbm, e.g. htdbm, fails.
It would be nice if specifying --with-dbm=gdbm would automatically add
--with-gdbm, or at least result in an error if --with-gdbm wasn't specified.
I've provided a patch that turns on --with-gdbm. An alternative would
be to fail the configure if --with-dbm=gdbm was requested and it didn't
find gdbm, whether because no --with-gdbm was given or it's just not
installed. I'm open to advice on which fits better with the usual
practice for autoconf.