diff --git a/lib/roken/roken.h b/lib/roken/roken.h
index 7f6204112..a7d816ee0 100644
--- a/lib/roken/roken.h
+++ b/lib/roken/roken.h
@@ -299,4 +299,6 @@ extern int opterr;
 extern const char *__progname;
 #endif
 
+void set_progname(char *argv0);
+
 #endif /*  __ROKEN_H__ */
diff --git a/lib/roken/roken.h.in b/lib/roken/roken.h.in
index 7f6204112..a7d816ee0 100644
--- a/lib/roken/roken.h.in
+++ b/lib/roken/roken.h.in
@@ -299,4 +299,6 @@ extern int opterr;
 extern const char *__progname;
 #endif
 
+void set_progname(char *argv0);
+
 #endif /*  __ROKEN_H__ */