diff --git a/tests/gpgscm/ffi.c b/tests/gpgscm/ffi.c
index 8e21ba6d3..305b7a135 100644
--- a/tests/gpgscm/ffi.c
+++ b/tests/gpgscm/ffi.c
@@ -35,6 +35,7 @@
 #include <unistd.h>
 
 #if HAVE_LIBREADLINE
+#define GNUPG_LIBREADLINE_H_INCLUDED
 #include <readline/readline.h>
 #include <readline/history.h>
 #endif