I'm trying to build gcc 4.6.1 on my iMac (Core 2 Duo) on Mac OS X 10.7.1. I used MacPorts (port) to install the MPC, GMP, and MPFR library files in /usr/local/lib. I configure by: sudo ~/tmp/gcc-4.6.1/configure --enable-languages=c,fortran,java,objc --enable-threads --with-cpu-64=x86-64 --with-gmp-lib=/usr/local/lib/ --with-mpfr-lib=/usr/local/lib/ --with-mpc-lib=/usr/local/lib/ But when I try to make, it terminates with this error: … checking size of long... 0 checking for long long... yes checking size of long long... configure: error: in `/Users/bhoglund/tmp/gcc46/gcc': configure: error: cannot compute sizeof (long long) See `config.log' for more details. make[2]: *** [configure-stage1-gcc] Error 77 make[2]: Leaving directory `/Users/bhoglund/tmp/gcc46' make[1]: *** [stage1-bubble] Error 2 make[1]: Leaving directory `/Users/bhoglund/tmp/gcc46' make: *** [all] Error 2 Thanks for any help. Bruce