It could be that gcc simply isn't in your path. What I mean is that when you execute a program from the command-line the computer (through the use of config files for your shell) knows what command programs live where.
Could also be a permissions issue. Try running the command and the root user and see if that yeilds different results. I find that this resolves *most* compile errors.
Example:
su root
<type root password>
./configure
I think that GAIM uses standard Make for its installation. Doublecheck the README for details. All else fails, just install the RPM for GAIM. You should be able to find it all over the place.
Good place for information?
http://gaim.sourceforge.net/faq.php#q1
Hope this helps. Let us know.