ORBit on AIX.

[mcnichol austin ibm com]

I am working on a port to AIX.

When using the native compiler and libc.a, I run into a
problem with the alloca call.

Is there some standard way to map this call to the
native malloc function?

I know I can just edit the offending files, but I think
it is a pain to do this every time.

Dan