diff -Naur unison-2.27.57.orig/Makefile.OCaml unison-2.27.57/Makefile.OCaml
--- unison-2.27.57.orig/Makefile.OCaml	2007-05-07 18:42:29 +0300
+++ unison-2.27.57/Makefile.OCaml	2008-02-23 18:01:40 +0200
@@ -182,7 +182,7 @@
 # File extensions will be substituted for the native code version
 OCAMLLIBS+=unix.cma str.cma
 
-COBJS+=osxsupport$(OBJ_EXT) pty$(OBJ_EXT)
+COBJS+=osxsupport$(OBJ_EXT) pty$(OBJ_EXT) openpty$(OBJ_EXT)
 
 ########################################################################
 ### User Interface setup
diff -Naur unison-2.27.57.orig/openpty.c unison-2.27.57/openpty.c
--- unison-2.27.57.orig/openpty.c	1970-01-01 03:00:00 +0300
+++ unison-2.27.57/openpty.c	2008-02-23 18:08:02 +0200
@@ -0,0 +1,146 @@
+/* Copyright (C) 1998, 1999, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* EK: This is a copy of openpty.c from glibc v.2.6, which is used as a
+   workaround to push unison build on glibc v.2.5 */ 
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <pty.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+// EK: Workaround for the original glibc __set_errno
+#ifndef __set_errno
+#define __set_errno(e) (errno = (e))
+#endif
+
+/* Return the result of ptsname_r in the buffer pointed to by PTS,
+   which should be of length BUF_LEN.  If it is too long to fit in
+   this buffer, a sufficiently long buffer is allocated using malloc,
+   and returned in PTS.  0 is returned upon success, -1 otherwise.  */
+static int
+pts_name (int fd, char **pts, size_t buf_len)
+{
+  int rv;
+  char *buf = *pts;
+
+  for (;;)
+    {
+      char *new_buf;
+
+      if (buf_len)
+	{
+	  rv = ptsname_r (fd, buf, buf_len);
+
+	  if (rv != 0 || memchr (buf, '\0', buf_len))
+	    /* We either got an error, or we succeeded and the
+	       returned name fit in the buffer.  */
+	    break;
+
+	  /* Try again with a longer buffer.  */
+	  buf_len += buf_len;	/* Double it */
+	}
+      else
+	/* No initial buffer; start out by mallocing one.  */
+	buf_len = 128;		/* First time guess.  */
+
+      if (buf != *pts)
+	/* We've already malloced another buffer at least once.  */
+	new_buf = realloc (buf, buf_len);
+      else
+	new_buf = malloc (buf_len);
+      if (! new_buf)
+	{
+	  rv = -1;
+	  __set_errno (ENOMEM);
+	  break;
+	}
+      buf = new_buf;
+    }
+
+  if (rv == 0)
+    *pts = buf;		/* Return buffer to the user.  */
+  else if (buf != *pts)
+    free (buf);		/* Free what we malloced when returning an error.  */
+
+  return rv;
+}
+
+/* Create pseudo tty master slave pair and set terminal attributes
+   according to TERMP and WINP.  Return handles for both ends in
+   AMASTER and ASLAVE, and return the name of the slave end in NAME.  */
+int
+openpty (int *amaster, int *aslave, char *name, struct termios *termp,
+	 struct winsize *winp)
+{
+#ifdef PATH_MAX
+  char _buf[PATH_MAX];
+#else
+  char _buf[512];
+#endif
+  char *buf = _buf;
+  int master, slave;
+
+  master = getpt ();
+  if (master == -1)
+    return -1;
+
+  if (grantpt (master))
+    goto fail;
+
+  if (unlockpt (master))
+    goto fail;
+
+  if (pts_name (master, &buf, sizeof (_buf)))
+    goto fail;
+
+  slave = open (buf, O_RDWR | O_NOCTTY);
+  if (slave == -1)
+    {
+      if (buf != _buf)
+	free (buf);
+
+      goto fail;
+    }
+
+  /* XXX Should we ignore errors here?  */
+  if(termp)
+    tcsetattr (slave, TCSAFLUSH, termp);
+  if (winp)
+    ioctl (slave, TIOCSWINSZ, winp);
+
+  *amaster = master;
+  *aslave = slave;
+  if (name != NULL)
+    strcpy (name, buf);
+
+  if (buf != _buf)
+    free (buf);
+  return 0;
+
+ fail:
+  close (master);
+  return -1;
+}
+//libutil_hidden_def (openpty)
diff -Naur unison-2.27.57.orig/openpty.h unison-2.27.57/openpty.h
--- unison-2.27.57.orig/openpty.h	1970-01-01 03:00:00 +0300
+++ unison-2.27.57/openpty.h	2008-02-23 18:02:45 +0200
@@ -0,0 +1,3 @@
+#ifndef __set_errno
+#define __set_errno(e) (errno = (e))
+#endif