diff --git a/src/getopt.h b/src/getopt.h
index ddf6fdda..9a4b1374 100644
--- a/src/getopt.h
+++ b/src/getopt.h
@@ -33,6 +33,7 @@ extern "C" {
    each non-option ARGV-element is returned here.  */
 
 extern char *optarg;
+extern int __getopt_initialized;
 
 /* Index in ARGV of the next element to be scanned.
    This is used for communication to and from the caller