diff -r fb8d7a666bed Modules/posixmodule.c
--- a/Modules/posixmodule.c	Tue Aug 30 00:28:40 2011 +0200
+++ b/Modules/posixmodule.c	Fri Sep 02 07:35:59 2011 +0200
@@ -2797,6 +2797,10 @@
 }  /* end of posix_listdir */
 
 #ifdef HAVE_FDOPENDIR
+# if defined(__OpenBSD__)
+extern DIR *fdopendir(int fd);
+# endif
+
 PyDoc_STRVAR(posix_fdlistdir__doc__,
 "fdlistdir(fd) -> list_of_strings\n\n\
 Like listdir(), but uses a file descriptor instead.\n\