Here are a few tips from James MacLean on
making Bacula work on an AIX system -- 15 Mar 2003:

Hi Folks,

I expect that an AIX with all the latest patches and a proper gcc will
compile. It is a boring story as Kern knows :), but here are the
highlights todate.

I have had success with :

/usr/local/bin/gcc -v
Reading specs from /usr/local/lib/gcc-lib/powerpc-ibm-aix4.1.5.0/egcs-2.91.60/specs
gcc version egcs-2.91.60 19981201 (egcs-1.1.1 release)

Which was installed from www-frec.bull.com. But with that release, it 
collides with sys/types.h from AIX and I had to redefine on my own in 
src/bacula.h :

typedef int            crid_t;
typedef int            __daddr_t;
typedef unsigned int class_id_t;

With that I have had all parts of bacula running and did backups and a 
restore fine. 

So I then went to IBM's own (current) gcc :

/opt/freeware/GNUPro/bin/gcc -v
Reading specs from /opt/freeware/GNUPro/lib/gcc-lib/powerpc-ibm-aix4.3.3.0/2.9-aix51-020209/specs
gcc version 2.9-aix51-020209

from http://www-1.ibm.com/servers/aix/products/aixos/linux/download.html

And found that it was not creating libbac.a correctly. Since then I've 
been trying to compile my own gcc only to find out last night after I 
broke down and looked at the GCC docs that there was a known bug in the 
AIX "as" compiler, for which there was a patch, and I have since applied. 

So now I am trying again to compile my own gcc, so that I can then try to 
compile Bacula and be comfortable that all is well with the latest Bacula 
and GCC.

We are at AIX oslevel 4.3.3.0, so even though we brought it right up to
date 150 days ago, there is already 250Megs of patches for it :(. So there 
may be more to this story :).

Bottom line is, yes it does work :), but because of our intstallation 
here, your setup might need to be tweaked to compile it... Then again it 
may not :).

How's that for a confusing Saturday story ;).

take care,
JES