AIX errors while compiling TPC-H data generator

If you get an error about missing DBGenOptions while trying to make the dbgen program from TPC-H on AIX using the xlc compiler, add the -qcpluscmt compiler option in the makefile. That should make sure the build goes through.
If you then get a runtime error on AIX 5.3 or higher such as:
$ ./dbgen
Could not load program ./dbgen:
System error: Not enough space

This could be because the program has to be compiled for 64 bit. Use the -q64 option in the makefile and rebuild. In other words, the following line in the makefile will help:
CC =xlc -qcpluscmt -q64

The other reason this can happen is if ulimit settings for data/stack are too low for the user. Try resetting these to unlimited first.