Add some missing includes for the build against stdcxx.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161657 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/StringRef.h

@@ -12,6 +12,7 @@
 
 #include "llvm/Support/type_traits.h"
 
+#include <algorithm>
 #include <cassert>
 #include <cstring>
 #include <limits>

lib/Target/X86/X86ISelLowering.cpp

@@ -49,6 +49,7 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Target/TargetOptions.h"
 #include <bitset>
+#include <cctype>
 using namespace llvm;
 
 STATISTIC(NumTailCalls, "Number of tail calls");

utils/TableGen/StringToOffsetTable.h

@@ -14,6 +14,7 @@
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/raw_ostream.h"
+#include <cctype>
 
 namespace llvm {