I forgot about a slight difference between AIX 5.1 and earlier and AIX 
5.2 and later:

AIX 5.2 introduced the C99 runtime and headers, so ffi.h.in needs a 
further patch to compile with IBM XLC on AIX 5.2 or later which has 
LLONG_MAX.

Sorry, I only tested on my Mozilla build host running AIX 5.1 :-(

AIX native preprocessor needs non-integer literals properly suffixed.

-- 
Uli Link