multiple gcc versions and selectability
 

slack 9.0 has gcc 3.2.2 installed on my setup,but now i need an earlier gcc to compile ibm's omni. can i install another gcc and select for it as compiler on a case by case basis?

yes.
i can't remember how you are supposed to do it, but
you can compile gcc 2.95.3 or whatever and install
it in /opt or something, or /usr/local/ if you want.
make backups of gcc, g++, and c++ in case the new
compiler over writes them. then make a little script to
do your switch job.