Special instructions for AIX

Under AIX, it is critical that you define an envirnment variable indicating whether you are building 64 or 32 bit libraries, and this definition must match what you pass to configure via the -b flag. You need to define the environment variable OBJECT_MODE to either 64 or 32, depending on which of these you pass to configure using the -b flag. So, if you are building 64-bit libraries and you use a bash derivative shell, you would issue export OBJECT_MODE=64 before starting the ATLAS configure step. On the other hand, if you use a csh derivative shell and want to build 32 but libaries, you would need to issue setenv OBJECT_MODE 32 before the build step.