Don't rely in <algorithm> being pulled in transitively.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139684 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/DebugInfo/DWARFDebugArangeSet.cpp b/lib/DebugInfo/DWARFDebugArangeSet.cpp
index 76e02f7..a3e2e62 100644
--- a/lib/DebugInfo/DWARFDebugArangeSet.cpp
+++ b/lib/DebugInfo/DWARFDebugArangeSet.cpp
@@ -10,6 +10,7 @@
 #include "DWARFDebugArangeSet.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
+#include <algorithm>
 #include <cassert>
 using namespace llvm;