One of our main compute systems until 2016 was an IBM Power6 called blizzard running on AIX 6.1.
configure && make && make install works just find, but the IBM compiler
xlc_r needs some special handling. In our case appending
CC=xlc_r CFLAGS="-g -O3 -q64 -qhot -qarch=auto -qtune=auto -qsmp=omp -DHAVE_MMAP"to the
configurecall is optimal. For other systems, source:/trunk/cdo/config/default may be helpful. It's a collection of CDO configurations for different host/platforms.