LLVM Clang Switches MMX Intrinsics To Use SSE2 Instead

Following LLVM/Clang recently dropping support for AMD 3DNow! instructions, the open-source compiler stack is now pushing the MMX SIMD instruction set to a backseat. Moving forward the MMX intrinsics will not make use of MMX but rather be mapped to SSE2. This is all fine unless you are wanting to use this modern code compiler on an Intel Pentium MMX / Pentium II / Pentium III or AMD K6 / K7 processor from the late 90's...