Todo list:

Clean out all of the crappy hacks that have crept into to the source tree, move
them out into the appropriate file in the 'os' and 'cc' directories. I got rid
of a lot of them in 1.4.[23], but some remain.

Make cross-compiles easier


CPUs
----
UltraSPARC III

OSes
----
Hurd
Plan9
OS/2
OS/400
VMS
MacOS pre-X

Compilers
---------
IBM VisualAge C++ [uses NMAKE?]
Metrowerks [uses NMAKE?]
AIX CC
