Fix compile for NetBSD and OpenBSD (#11896)

libs/extc/process_stubs.c

@@ -38,7 +38,7 @@
 #	include <errno.h>
 #	include <string.h>
 #	ifndef __APPLE__
-#		if defined(__FreeBSD__) || defined(__DragonFly__)
+#		if defined(__FreeBSD__) || defined(__DragonFly__) || defined(__NetBSD__) || defined(__OpenBSD__)
 #			include <sys/wait.h>
 #		else
 #			include <wait.h>