Include cctype for isdigit.  Patch by Stephen Hines.

llvm-svn: 151973
diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index 8af2c88..f19e6e3 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -24,6 +24,7 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 #include "llvm/Transforms/Utils/ValueMapper.h"
+#include <cctype>
 using namespace llvm;
 
 //===----------------------------------------------------------------------===//