Make --with-erlang work with the new use of AC_ERLANG_PATH_ERL.
Make --with-erlang work with the new use of AC_ERLANG_PATH_ERL.

The locating of 'erl' and 'erlc' in a user supplied directory needed
to happen before calling the autoconf erlang stuff, otherwise the
Erlang library detection could end up using another version of Erlang
than the one requested by the user.

bernardd/yxa,bernardd/yxa,bernardd/yxa,bernardd/yxa