LLVMdev Digest, Vol 64, Issue 6

I am running this version of gcc:
$ gcc --version
i686-apple-darwin9-gcc-4.0.1 (GCC) 4.0.1 (Apple Inc. build 5465)

From here: Getting Started with the LLVM System — LLVM 18.0.0git documentation

  "We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1 successfully
with them (however, see important notes below)."
I'm not sure what the "important notes below" are for gcc 4.0.1 as
none of the notes I saw below seemed relevant to 4.0.1.

So my example (posted previously) is pretty simple. As far as I can
tell, it is the canonical way to compile "int main(int argc) {return
argc;}". If that doesn't work, how can gcc 4.0.1 be working at all?
Just trying to figure out what is going on here and how to proceed.

Daniel