Fix some compilation errors on msvc:

- "Redefinition of I" (iterator masks previous definition)
- include missing header file

Patch by Argiris Kirtzidis!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48115 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/IPO/ExtractGV.cpp

@@ -17,6 +17,7 @@
 #include "llvm/Constants.h"
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Support/Compiler.h"
+#include <algorithm>
 using namespace llvm;
 
 namespace {