After a grueling battle trying to compile GIT from source on an AIX (6.1) machine, I thought I would try to save you some trouble and outline clearly what I had to do. Please note I initially followed this guide, which gave me a good base, but I had to throw in a few extra tweaks.
First off, you will need to get the following dependencies. I was able to get most of them from the IBM Linux Toolbox here, and the rest I got from the great people at Perzl.org
Dependencies:
bison-1.875-3.aix5.1.ppc.rpm
coreutils-5.2.1-2.aix5.1.ppc.rpm
expect-5.45-1.aix5.1.ppc.rpm
flex-2.5.4a-6.aix4.3.ppc.rpm
gcc-4.2.0-3.aix6.1.ppc.rpm
gcc-cplusplus-4.2.0-3.aix6.1.ppc.rpm
gdbm-1.8.3-5.aix5.2.ppc.rpm
gettext-0.10.40-8.aix5.2.ppc.rpm
git-git-5bc2dc2
git-git-v1.7.10.2-569-g5bc2dc2.zip
libXft-2.2.0-1.aix5.1.ppc...