Only make actual directory names canonical

If the directory that is specified does not exist, then keep the path
as entered, which makes for better error messages later.

We cannot print an warning on a non-existent name, because it may be
target directories that are specified, or perhaps logical options
(like --with-mpi=yes)

configure

@@ -146,7 +146,7 @@ for OPT in "$@"; do
           eval pkgloc=$(printf "%q" "${pkgloc}")
           # expand to full path since CMake changes to source directory (!)
           # this also normalize the path name wrt. not having a trailing slash
-          pkgloc=$(test -d "${pkgloc}" && sh -c "cd \"${pkgloc}\"; pwd")
+          test -d "${pkgloc}" && pkgloc=$(sh -c "cd \"${pkgloc}\"; pwd")
           # special aliases
           case "${pkgname}" in
             umfpack)