[tlbuild] Legacy Darwin

[Mojca Miklavec]

Dear Karl,

Is there any need/desire (or rather: time) to document what was done
on Legacy Darwin to build the binaries? I know that Dick sends a huge
zip with instructions for the newer mac.

I only now committed the asy binaries. Sorry for the super long delay,
but I wasn't quite sure how to "properly" build it (I built them long
before, but then everyone told me that asy is useless without some
libraries like gsl, fftw, readline, ...). After Dick sent me some more
detailed instructions here's what I ended up with:
    https://github.com/TeXLive-M/build-asymptote
I might move it to the automatic build setup one day, just not now.

(So we now have asymptote for powerpc as well. Not that anyone would
use it, but there was no extra work once I got the dependencies in
place, otherwise I wouldn't have done it.)

The missing bits and pieces:

- I didn't build wget (because there were some issues and library
dependencies that I wasn't happy about; and the old one should be fine
though.)

- I didn't build dvisvgm (getting C++11 code to build in a portable
way is somewhat tricky, I'll see whether I'll bite that bullet next
year or just drop support for 10.6 and lower).

- I didn't rebuild xindy for i386 and powerpc. There were issues with
cross-compilation, I don't have a i386 machine and I don't consider
powerpc worth turning up and going through the trouble of compilation
just for that. But more important: I doubt anyone would actually mind.

Mojca