1 files changed, 3 insertions, 1 deletions
diff --git a/osx.m b/osx.m
index 0793817..ee9161f 100644
--- a/osx.m
+++ b/osx.m
@@ -77,7 +77,9 @@
  *    recreate it.
  */
 
-#define COMBINED /* we put all the puzzles in one binary in this port */
+#ifndef COMBINED
+#error Expected -DCOMBINED to come from the makefile
+#endif
 
 #include <ctype.h>
 #include <time.h>