building gcc against eclipse?

   In fink, we have been building the gcj ecj1 support by
copying the ecj-latest.jar file from ftp://sourceware.org/pub/java
into the top level of the gcc source directory. I would like to try
building gcc on darwin with the eclipse compiler instead. We have
a fink ecj package which provides...

/.
/sw
/sw/bin
/sw/bin/ecj
/sw/share
/sw/share/doc
/sw/share/doc/ecj
/sw/share/doc/ecj/about.html
/sw/share/java
/sw/share/java/ecj
/sw/share/java/ecj/ecj.jar

How exactly does one build the gcj against this ecj compiler? 
Would creating a symlink in the toplevel gcc directory to
/sw/share/java/ecj/ecj.jar be sufficient to cause the installed
eclipse compiler to be used for ecj1?
     Thanks in advance for any advice.
              Jack