*.mk files modified for compatibility with Mentor Sourcery CodeBench Lite toolchain

Makefiles and sources modified for compatibility with the latest Mentor Sourcery CodeBench Lite toolchain (gcc 4.8.1). You can download the Linux or Windows binary package from Mentor site: https://sourcery.mentor.com/GNUToolchain/release2641

This toolchain is the official GCC compiler supported by MIPS/Imagination. It has all the features implemented in pic32mz processor: microMIPS, DSP, all variants of floating point library.