1 files changed, 1 insertions, 0 deletions
diff --git a/common.h b/common.h
index 5bfac1e..2df927b 100644
--- a/common.h
+++ b/common.h
@@ -6,6 +6,7 @@
 # pragma clang diagnostic ignored "-Wcovered-switch-default"
 #endif
 #include "libhashsum.h"
+#include <ctype.h>
 #include <errno.h>
 #include <limits.h>
 #include <string.h>