Hello, I'm writing with what is probably a very simple question about the build_clib command in distutils. My problem is that I have part of a library that I am building which should be built with no optimization (O0) instead of the default O2 (with gcc). After various attempts, I ended up subclassing the "build_clib" class so that I could pass the "extra_preargs" argument in the call to "self.compiler.compile" in the class's "build_libraries" method. Unfortunately, both O2 (the default) and O0 now appear in the compilation options and the first (O2!) takes precedence it seems. I wonder if you have come across this problem and whether you have a solution? I would really appreciate any help that you can give me. Many thanks. Best regards, Martin Field.