diff --git a/configure b/configure
index 187df527..a8cd07b7 100755
--- a/configure
+++ b/configure
@@ -199,11 +199,10 @@ fi
 
 if [ -n "$DEBUG" -a "$DEBUG" != no -a "$DEBUG" != false ]; then
 	echo "Building with debugging symbols."
+	echo "CPPFLAGS += -DDEBUG" >>$CONFIG_MK
 	echo "CFLAGS +=	-g" >>$CONFIG_MK
 fi
 
-echo "CPPFLAGS +=	-DDEBUG" >>$CONFIG_MK
-
 case "$OS" in
 linux)
 	echo "CPPFLAGS += 	-D_XOPEN_SOURCE=700" >>$CONFIG_MK
diff --git a/include/xbps_api_impl.h b/include/xbps_api_impl.h
index fcb2dd4a..32422e61 100644
--- a/include/xbps_api_impl.h
+++ b/include/xbps_api_impl.h
@@ -27,6 +27,10 @@
 #ifndef _XBPS_API_IMPL_H_
 #define _XBPS_API_IMPL_H_
 
+#ifndef DEBUG
+#define NDEBUG
+#endif
+
 #include <assert.h>
 #include <confuse.h>
 #define LIBXBPS_PRIVATE