-- MACOSX_SDK=/Developer/SDKs/MacOSX10.3.9.sdk
-- GCC_VERSION=3.3
-- ARCH="-arch ppc"
-- MACOSX_SDK_CFLAGS="-nostdinc -isystem ${MACOSX_SDK}/usr/include/gcc/darwin/${GCC_VERSION} -isystem ${MACOSX_SDK}/usr/include"
-- MACOSX_SDK_CXXFLAGS="-nostdinc++ -I${MACOSX_SDK}/usr/include/gcc/darwin/${GCC_VERSION}/c++ -I${MACOSX_SDK}/usr/include/gcc/darwin/${GCC_VERSION}/c++/ppc-darwin -I${MACOSX_SDK}/usr/include/gcc/darwin/${GCC_VERSION}/c++/backward"
-- MACOSX_SDK_LDFLAGS="-L${MACOSX_SDK}/usr/lib/gcc/darwin -L${MACOSX_SDK}/usr/lib/gcc/darwin/${GCC_VERSION} -L${MACOSX_SDK}/usr/lib"
+- MACOSX_SDK="${MACOSX_SDK:-/Developer/SDKs/MacOSX10.3.9.sdk}"
+- GCC_VERSION="${GCC_VERSION:-3.3}"
+- ARCH="${ARCH:--arch ppc}"
+- MACOSX_SDK_CFLAGS="${MACOSX_SDK_CFLAGS:--nostdinc -isystem ${MACOSX_SDK}/usr/include/gcc/darwin/${GCC_VERSION} -isystem ${MACOSX_SDK}/usr/include}"
+- MACOSX_SDK_CXXFLAGS="${MACOSX_SDK_CXXFLAGS:--nostdinc++ -I${MACOSX_SDK}/usr/include/gcc/darwin/${GCC_VERSION}/c++ -I${MACOSX_SDK}/usr/include/gcc/darwin/${GCC_VERSION}/c++/ppc-darwin -I${MACOSX_SDK}/usr/include/gcc/darwin/${GCC_VERSION}/c++/backward}"
+- MACOSX_SDK_LDFLAGS="${MACOSX_SDK_LDFLAGS:--L${MACOSX_SDK}/usr/lib/gcc/darwin -L${MACOSX_SDK}/usr/lib/gcc/darwin/${GCC_VERSION} -L${MACOSX_SDK}/usr/lib}"
+- ;;
+- x*86_64*darwin*)
+- MACOSX_SDK="${MACOSX_SDK:-/Developer/SDKs/MacOSX10.5.sdk}"
+- GCC_VERSION="${GCC_VERSION:-4.0}"
+- ARCH="${ARCH:--arch i386}"
+- MACOSX_SDK_CFLAGS="${MACOSX_SDK_CFLAGS:--isysroot ${MACOSX_SDK}}"
+- MACOSX_SDK_CXXFLAGS="${MACOSX_SDK_CXXFLAGS:-${MACOSX_SDK_CFLAGS}}"