diff --git a/lib/roken/get_window_size.c b/lib/roken/get_window_size.c
index 6edb1c405..54789ad2c 100644
--- a/lib/roken/get_window_size.c
+++ b/lib/roken/get_window_size.c
@@ -49,6 +49,10 @@ RCSID("$Id$");
 #include <sys/types.h>
 #endif
 
+#ifdef HAVE_SYS_PROC_H
+#include <sys/proc.h>
+#endif
+
 #ifdef HAVE_SYS_TTY_H
 #include <sys/tty.h>
 #endif