Unbreak C++ build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35067 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ExecutionEngine/ExecutionEngine.cpp

@@ -24,6 +24,7 @@
 #include "llvm/Support/MutexGuard.h"
 #include "llvm/System/DynamicLibrary.h"
 #include "llvm/Target/TargetData.h"
+#include <math.h>
 using namespace llvm;
 
 STATISTIC(NumInitBytes, "Number of bytes of global vars initialized");