Uniaud32 Makefile improvements from Mike

[gentux2]

Mike Greene wrote a new set of Makefiles for Uniaud32 some time ago, and I was unable to commit them because they only work when compiling with wasm, which, in this incarnation, requires a modified DDK, which has licensing issues for both the DDK and the GPL.

However, apart from this, they contain a number of improvements over the existing system, which I have always intended to apply. After all, he did go to the work to do it. This ticket is to remind myself of this.