I have compile picolisp 2.3.x (at least 2.3.3 or later..) on a PPC
mac. The 1st thing to do is to have the Developer CD that came with
the Mac installed. All the compilers and build tools are in there. In
your case, it can't find gcc, so that might be the problem. If you
bought yr Mac earlier, you may need to download and upgrade the
Developer CD/SDK's. As I remember there being a transition from gcc3.x
to gcc4 made during towards the end of the 10.4.x versions that may
cause some problems.
I had it working on my PPC Mac, 10.4.9/10 before, but unfortunately,
that machine is now broken. I also remember having to tweak the shell
var MACOSX_DEPLOYMENT_TARGET to the actual OS version...
I'm sorry I'm typing all this from memory, as that machine is now 1/2
dead, well the screen went blank, I have'nt had time to see if I can
use an external monitor, and I don't have one to spare at the moment.
I'm typing this on an Intel Mac, and I've not got picolisp on this,
have tried the 64bit picolisp, but won't compile on my 10.5.7.