libgcj/5773: integrate addr2line and c++filter into libjava instead of using an external process.

[Bryce McKinlay]

Unfortunatly we can't link libgcj against BFD due to legal/license 
issues, ie BFD is GPL ;-(

We do have some other ideas about how to do stack traces when addr2line 
etc arn't available; see the recent discussion on java@gcc.gnu.org

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5773