I’ve tried GCCE version 4 before for building Symbian software, but have been somewhat put off by all the warnings it produces, mostly due to incompatibilities with the header files in the existing S60 SDKs. Well, I finally managed to get a working S60 application built with GCCE 4 without any warnings. Mind you, this was just one application, and not built with the full Symbian toolchain, but still.