diff -r e28221e52d24 Modules/_posixsubprocess.c
--- a/Modules/_posixsubprocess.c	Thu Apr 02 16:25:01 2015 +0200
+++ b/Modules/_posixsubprocess.c	Thu Apr 02 17:12:59 2015 +0200
@@ -35,7 +35,7 @@
 # endif
 #endif
 
-#if defined(__FreeBSD__) || (defined(__APPLE__) && defined(__MACH__))
+#if defined(__FreeBSD__) || (defined(__APPLE__) && defined(__MACH__)) || defined(__OpenBSD__)
 # define FD_DIR "/dev/fd"
 #else
 # define FD_DIR "/proc/self/fd"