Bug#850150: freemat ftbfs with LLVM 3.9

[Graham Inggs]

Control: tags -1 patch

Gianfranco found that in LLVM 3.9, llvm/Target/TargetOptions.h now has:
#include "llvm/MC/MCAsmInfo.h"
which was not present in LLVM 3.8.

I tested the workaround below, which can be used until #850785 is fixed.

--- a/libs/libMatC/CJitFuncClang.hpp
+++ b/libs/libMatC/CJitFuncClang.hpp
@@ -5,6 +5,8 @@
  #include <string>

  #include "llvm/IR/Function.h"
+/* workaround for Debian bug #850785 */
+#undef X86
  #include "llvm/ExecutionEngine/ExecutionEngine.h"
  #include "llvm/IR/LLVMContext.h"
  #include "clang/Frontend/CompilerInstance.h"