include OpenBSD in ifdef

Index: libs/extc/process_stubs.c
--- libs/extc/process_stubs.c.orig
+++ libs/extc/process_stubs.c
@@ -37,7 +37,7 @@
 #	include <errno.h>
 #	include <string.h>
 #	ifndef __APPLE__
-#		if defined(__FreeBSD__) || defined(__DragonFly__)
+#		if defined(__FreeBSD__) || defined(__DragonFly__) || defined(__OpenBSD__)
 #			include <sys/wait.h>
 #		else
 #			include <wait.h>