The latest version of gcc for A/UX 3.0 and 3.0.1 is 2.4.5. It is available
from anonymous ftp on jagubox.gsfc.nasa.gov (128.183.44.1) under the
/pub/aux directory.
You might also need to get a copy of gzip package (also in jagubox) to
uncompress files since it is in gz (gnu compressed) format.