More new ABI ramblings

[Andrew Haley]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=9861 suggests that the
return type ought to be taken into account when generating a mangled
name.

This class, generated from Generic Java, has two methods that look like this:

  Method name:"x" protected Signature: 13=()java.lang.Integer
  Attribute "Code", length:21, max_stack:3, max_locals:1, code_length:9

  Method name:"x" protected Signature: 16=()java.lang.Object
  Attribute "Code", length:17, max_stack:1, max_locals:1, code_length:5
  Attribute "Synthetic", length:0

Is there anything that we can do to disambiguate such cases?  Perhaps
we could change the Java name mangling so that it really does contain
the return type, and change the C++ compiler to match.

Andrew.