diff --git a/src/include/options-generator.c b/src/include/options-generator.c
index aa2ff8f5..8f953343 100644
--- a/src/include/options-generator.c
+++ b/src/include/options-generator.c
@@ -21,7 +21,6 @@
  * @brief Generates code based on Recutils database
  * @author Christian Grothoff
  */
-#define _GNU_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>