Fix build to work with LLVM top-of-tree again

llvmutil.h

@@ -38,10 +38,17 @@
 #ifndef ISPC_LLVMUTIL_H
 #define ISPC_LLVMUTIL_H 1
 
-#include <llvm/LLVMContext.h>
-#include <llvm/Type.h>
-#include <llvm/DerivedTypes.h>
-#include <llvm/Constants.h>
+#if defined(LLVM_3_0) || defined(LLVM_3_1) || defined(LLVM_3_2)
+  #include <llvm/LLVMContext.h>
+  #include <llvm/Type.h>
+  #include <llvm/DerivedTypes.h>
+  #include <llvm/Constants.h>
+#else
+  #include <llvm/IR/LLVMContext.h>
+  #include <llvm/IR/Type.h>
+  #include <llvm/IR/DerivedTypes.h>
+  #include <llvm/IR/Constants.h>
+#endif
 
 namespace llvm {
     class PHINode;