diff --git a/libfreefare/ntag21x.c b/libfreefare/ntag21x.c
index 131bf56..ece1fcf 100644
--- a/libfreefare/ntag21x.c
+++ b/libfreefare/ntag21x.c
@@ -14,7 +14,9 @@
  * June 2015
  */
 
-#include "config.h"
+#if defined(HAVE_CONFIG_H)
+#  include "config.h"
+#endif
 
 #if defined(HAVE_SYS_TYPES_H)
 #  include <sys/types.h>