Since switching to C++11 the NaCL build was disabled. This re-enables the ARM configuration which uses a more recent version of gcc. This means that that NaCl code paths will at least be test until we can find a way to re-enable the X86 build.
This allows the linux and NaCl builds (and perhaps others) to be compiles with -Wall and -Werror, and it makes the build output much less noisy.