diff --git a/library/dir.m b/library/dir.m
index 580d92810..66a2dd3b1 100644
--- a/library/dir.m
+++ b/library/dir.m
@@ -1323,11 +1323,11 @@ make_single_directory(DirName, Result, !IO) :-
         }
       #endif // EEXIST
     }
-    IsWin32Error = MR_NO
+    IsWin32Error = MR_NO;
 #else // !MR_WIN32 && !MR_HAVE_MKDIR
     Status = ML_MAKE_SINGLE_DIRECTORY_ERROR;
     Error = ENOSYS;
-    IsWin32Error = MR_NO
+    IsWin32Error = MR_NO;
 #endif
 ").