Add the following under “platform darwin 11”
if {${configure.compiler} == “clang”} { configure.compiler llvm-gcc-4.2 } configure.cflags-delete “-std=c99” configure.cflags-delete -O2 configure.cxxflags-delete -O2 configure.cflags-append -O0 configure.cxxflags-append -O0 ….