diff --git a/kitty/ringbuf.c b/kitty/ringbuf.c
index 3c138adb2..0c1b3921d 100644
--- a/kitty/ringbuf.c
+++ b/kitty/ringbuf.c
@@ -13,7 +13,9 @@
  * <http://creativecommons.org/publicdomain/zero/1.0/>.
  */
 
+#ifndef KITTY_DEBUG_BUILD
 #define NDEBUG 1
+#endif
 #include "ringbuf.h"
 
 #include <stdint.h>
diff --git a/setup.py b/setup.py
index bb3a507e1..d6a62247e 100755
--- a/setup.py
+++ b/setup.py
@@ -304,6 +304,9 @@ def init_env(
         cflags.append('-flto')
         ldflags.append('-flto')
 
+    if debug:
+        cflags.append('-DKITTY_DEBUG_BUILD')
+
     if profile:
         cppflags.append('-DWITH_PROFILER')
         cflags.append('-g3')