I am getting this when I build: (in /Users/Gp/projects/macruby) /usr/bin/gcc -std=c99 markgc.c -o markgc -Wno-format In file included from markgc.c:31: /usr/local/include/mach-o/arch.h:35: error: nested redefinition of ‘enum NXByteOrder’ /usr/local/include/mach-o/arch.h:35: error: redeclaration of ‘enum NXByteOrder’ /usr/local/include/mach-o/arch.h:36: error: redeclaration of enumerator ‘NX_UnknownByteOrder’ /usr/include/architecture/byte_order.h:147: error: previous definition of ‘NX_UnknownByteOrder’ was here /usr/local/include/mach-o/arch.h:37: error: redeclaration of enumerator ‘NX_LittleEndian’ /usr/include/architecture/byte_order.h:148: error: previous definition of ‘NX_LittleEndian’ was here /usr/local/include/mach-o/arch.h:39: error: redeclaration of enumerator ‘NX_BigEndian’ /usr/include/architecture/byte_order.h:150: error: previous definition of ‘NX_BigEndian’ was here rake aborted! Command failed with status (1): [/usr/bin/gcc -std=c99 markgc.c -o markgc -...] I am using SL on a Core 2 Duo iMac. Any thoughts? Cheers, -Gp