AIX configure are slow as hell

I'm compiling vim7 right now on AIX, and as usual, configure takes so much time and it's such a pain ...

/bin/sh is said to be an alias on ksh, that creates tons of temp files, and that takes a huge amount of time. exporting CONFIG_SHELL to bash never works for me. What works is manually editing the configure (under src/auto/ for vim) and replacing the shebang with #!/your/path/to/bash or #!/bin/env bash.

I'll probably see if I can compile dash on AIX, but bash is already way faster than
http://www.kernel.org/pub/scm/utils/dash/dash.git

By the way, due to link error with gettext and friends, I had to configure like this to have it working:

./configure --disable-nls CC=xlc_r