Add missing standard headers. Patch by Joerg Sonnenberger!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122193 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Unix/Host.inc b/lib/Support/Unix/Host.inc
index 5561906..ed74b67 100644
--- a/lib/Support/Unix/Host.inc
+++ b/lib/Support/Unix/Host.inc
@@ -20,6 +20,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "Unix.h"
 #include <sys/utsname.h>
+#include <cctype>
 #include <string>
 
 using namespace llvm;