I recently found and packaged up a version of geek gadgets or the Amiga Development Environment and put it on aminet. The URL is here and integration is easy peasy. It provides a 2.95.3 version of GCC with two lines of code added to the User-Startup or other startup script. Works on a plain OS 3.1 installation with no work.
http://aminet.net/package/dev/gcc/ADEFor AmiKit purposes, you may want to look closely at the internal libs directory to see if there will be any conflicts up front and either replace or do something with them in general.