my mind aix or adventures with ibm aix 6.1 XLcc++

# cc -V

cc:  1501-273 A mismatch exists between the OS level and the configuration file. The configuration file /etc/vac.cfg is intended for AIX 5.3. Use vac.cfg.61 to correct the problem.

What?

# ls -la /etc/ |grep vac

lrwxrwxrwx    1 root     system           10 Jan 18 08:51 vac.cfg -> vac.cfg.53
-rw-r--r--    1 bin      bin           32781 Jan 16 10:23 vac.cfg.50
-rw-r--r--    1 bin      bin           32876 Jan 16 10:23 vac.cfg.51
-rw-r--r--    1 bin      bin           37043 Jan 16 10:23 vac.cfg.52
-rw-r--r--    1 bin      bin           37045 Jan 16 10:23 vac.cfg.53

Not there. Okay...

# cp vac.cfg.53 vac.cfg.61
# vi vac.cfg.61

Remove the last lines:

oslevel   = 5.3
os_major  = 5
os_minor  = 3

Done.

# ln -s vac.cfg.61 vac.cfg
# chown bin.bin vac.cfg.61 
# cc -V

blah blah
I win.