isspace needs ctype include

Daniel Kroening · Daniel Kroening · commit 5ec88cda9eaf · 2016-12-08T10:38:26.000Z
diff --git a/src/util/string_utils.cpp b/src/util/string_utils.cpp
@@ -7,7 +7,7 @@ Author: Daniel Poetzl
 \*******************************************************************/
 
 #include <cassert>
-#include <iostream>
+#include <cctype>
 
 #include "string_utils.h"
 
