+#include <fcntl.h>
+#if defined __OpenBSD__
+# include <sys/ioctl.h>
+# include <sys/tty.h>
+#endif
+
+/* posix_openpt() is already provided on
+ glibc >= 2.2.1 (but is a stub on GNU/Hurd),
+ Mac OS X >= 10.4,
+ FreeBSD >= 5.1 (lived in src/lib/libc/stdlib/grantpt.c before 8.0),
+ NetBSD >= 3.0,
+ AIX >= 5.2, HP-UX >= 11.31, Solaris >= 10, Cygwin >= 1.7.
+ Thus, this replacement function is compiled on
+ Mac OS X 10.3, OpenBSD 4.9, Minix 3.1.8,
+ AIX 5.1, HP-UX 11.23, IRIX 6.5, OSF/1 5.1, Solaris 9,
+ Cygwin 1.5.x, mingw, MSVC 9, Interix 3.5, BeOS.
+ Among these:
+ - AIX has /dev/ptc.
+ - HP-UX 10..11, IRIX 6.5, OSF/1 5.1, Solaris 2.6..9, Cygwin 1.5
+ have /dev/ptmx.
+ - HP-UX 10..11 also has /dev/ptym/clone, but this should not be needed.
+ - OpenBSD 4.9 has /dev/ptm and the PTMGET ioctl.
+ - Minix 3.1.8 have a list of pseudo-terminal devices in /dev.
+ - On native Windows, there are no ttys at all. */