As I've recently acquired a Mac Mini, I decided to resurrect this thread with my new findings.
I created a fork of the GCW0 buildroot with some of my OSX patches:
https://github.com/zear/buildroot/commits/osx_fixesChanges:
* gmp: Workaround for Darwin assembler quirk.
* Remove gcc version check to allow for clang usage
In order to get past the sed problems mentioned by others above, one needs to install the GNU flavour of sed via
homebrew:
brew install gnu-sed
Then it's required to add gnu-sed location to PATH, so that the terminal will see this version instead of the default BSD flavour:
export PATH="/usr/local/opt/gnu-sed/libexec/gnubin:$PATH"
With those changes, I get as far as uclibc compilation, which fails at:
extra/scripts/unifdef.c:81:8: error: expected parameter declarator
size_t strlcpy(char *dst, const char *src, size_t siz);
The good thing however is that with my changes, the compilation process manages to
build the compiler, before it succumbs to the issue above.
It means that one can do a simple trick of
downloading the latest official x86 Linux toolchain, extracting it to /opt/gcw0-toolchain/ and then copying over the freshly built compiler, resulting in
a working GCW0 cross-compiler for OSX.
I have only tested it on my own software projects, but it compiles and the produced binaries/OPKs work fine.
There are some symlink issues and I can't guarantee that every thing necessary gets compiled before the compilation process fails, however this is already something useful to many.
Because of the mentioned quirks I won't be uploading a precompiled build, but at this point I assume that the interested parties are able to compile their own version based on my github fork/branch and the above tips.
