What's new:
-----------

- New, unified implementation of POSIX permission and ACL handling.  The
  new ACLs now store the POSIX ACL MASK/CLASS_OBJ permission mask, and
  they allow to inherit the S_ISGID bit.  ACL inheritance now really
  works as desired, in a limited, but theoretically equivalent fashion
  even for non-Cygwin processes.

  To accommodate Windows default ACLs, the new code ignores SYSTEM and
  Administrators group permissions when computing the MASK/CLASS_OBJ
  permission mask on old ACLs, and it doesn't deny access to SYSTEM and
  Administrators group based on the value of MASK/CLASS_OBJ when
  creating the new ACLs.

  The new code now handles the S_ISGID bit on directories as on Linux:
  Setting S_ISGID on a directory causes new files and subdirs created
  within to inherit its group, rather than the primary group of the user
  who created the file.  This only works for files and directories
  created by Cygwin processes.

- basename(3) now comes in two flavors, POSIX and GNU.  The POSIX version is
  the default.  You get the GNU version after

    #define _GNU_SOURCE
    #include <string.h>


What changed:
-------------

- The maximum number of PTYs has been raised from 64 to 128.


Bug Fixes
---------

- Fix potential hang in pseudo ttys when generating ECHO output while the slave
  is flooding the pty with output.
  Addresses: https://cygwin.com/ml/cygwin/2015-03/msg00019.html

- Fix potential premature SIGHUP in pty code.
  Addresses: https://cygwin.com/ml/cygwin/2015-03/msg00070.html

- Fix a name change from symlink to target name in calls to execvp, system, etc.
  Addresses: https://cygwin.com/ml/cygwin/2015-03/msg00270.html

- Fix internal error in pty -ONLCR handling.  Fix timing bug in pty OPOST 
  handling.
  Addresses: https://cygwin.com/ml/cygwin/2015-02/msg00929.html

- Avoid creating passwd and group records from fully qualified Windows
  account names (domain\name, name@domain).
  Addresses: https://cygwin.com/ml/cygwin/2015-03/msg00528.html

- Avoid potential crash at startup or in getgroups(2).
  Addresses: https://cygwin.com/ml/cygwin/2015-04/msg00010.html

- Fix UTF-16 surrogate handling in wctomb and friends.
  Addresses: https://cygwin.com/ml/cygwin/2015-03/msg00452.html

- Fix shmget usage of size parameter for already existing segments.
  Addresses: https://cygwin.com/ml/cygwin/2015-04/msg00105.html