#define of _XOPEN_SOURCE is needed to obtain the header for ptsname.

if _XOPEN_SOURCE is not defined before including stdlib.h, a warning about
a assignment from an integer to a pointer without a cast will occur.  This
warning could actually cause problems in some circumstances, because the
upper bits of the return value could, potentially, be set to zero before
the assignment is made.
Index: library/openpty.c
===================================================================
--- library.orig/openpty.c
+++ library/openpty.c
@@ -8,6 +8,10 @@
  * Contributors:
  *     QNX Software Systems - initial API and implementation
  *******************************************************************************/
+
+
+/* _XOPEN_SOURCE is needed to bring in the header for ptsname */
+#define _XOPEN_SOURCE
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/ioctl.h>