Patch to enable libgcj.dll for MinGW

[TJ Laurenzo]

> even though an inline body is provided.  If the C++ compiler can prove
> that an object is an instance of a and not one of its subclasses, it
> can inline the body.  If it can't prove that, it won't do the
> inlining.
Thanks for the correction.  So, for platforms that support it, the
optimization is indeed  semantically correct.  Can we decide what to
do with it?  I am still in favor of removing the code entirely, but if
the decision is to go with a "--disable-inline" option, I will code
that up and submit the patch.

TJ