Hi all, Thanks for all of your replies. 1) --enable-languages I put in everything except ada (because I didn't have a dependency) and go (because it was causing errors). The build didn't go smoothly either - I had to remove config.cache (all of them) in the middle when there was an error regarding config.cache. 2) I did download the complete gcc. the directories gcc/cp and gcc/fortran exist. 3) Do you mean something you built with this gcc has the error. Or trying to run the compiler itself generates the error? Trying to run the compiler itself generates the error 4) I am now trying to run the compiler on some code, and I am getting the following errors: /usr/local/lib/gcc/i386-apple-darwin10.7.0/4.6.1/../../../../include/c++/4.6 .1/tr1/cmath:337:5: error: expected ?)¹ before ?__f¹ This is what that line looks like: fpclassify(_Tp __f) There's a lot of errors like that. Regards, Anna.