diff --git a/divelist.h b/divelist.h
index e3ff1be09..47680f9b2 100644
--- a/divelist.h
+++ b/divelist.h
@@ -3,9 +3,13 @@
 
 #ifdef __cplusplus
 extern "C" {
-#endif
-
+#else
+#if __STDC_VERSION__ >= 199901L
 #include <stdbool.h>
+#else
+typedef int bool;
+#endif
+#endif
 
 struct dive;