Follow the usual installation instructions.  Begin with

		config.gcc rs6000

GCT must be built with "cc", not "xlc" or "c89".
When making, you'll see some messages about macro redefinitions.  
These are harmless.  (The AIX compiler, unlike most C compilers,
complains about redefinitions even if the new definition is identical
to the old.)

The test suite is known to pass when the gct-ansi script is used,
using either "cc" or "xlc".  It will probably work with "c89", but I
haven't tried it.  You cannot use the gct-trad script, even with "cc".

A few of the weak mutation tests fail.  I have not examined these
carefully - at least one is a test error.  The others are probably
ordinary unportabilities.

