Fix for gcc3.4: invalid use of forward delacred class on line 93

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13370 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/InstVisitor.h

@@ -51,11 +51,10 @@
 #define LLVM_SUPPORT_INSTVISITOR_H
 
 #include "llvm/Function.h"
+#include "llvm/Module.h"
 
 namespace llvm {
 
-class Module;
-
 // We operate on opaque instruction classes, so forward declare all instruction
 // types now...
 //