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

- Add 24 bit color support using xterm compatibility mode in Windows 10
  1703 or later.  Add fake 24 bit color support for legacy console,
  which uses the nearest color from 16 system colors.


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

- FIFOs can now be opened multiple times for writing.
  Addresses: https://cygwin.com/ml/cygwin/2015-03/msg00047.html
             https://cygwin.com/ml/cygwin/2015-12/msg00311.html

- If a SA_SIGINFO signal handler changes the ucontext_t pointed to by
  the third parameter, follow it after returning from the handler.

- Eliminate a header file name collision with <X11/XLocale.h> on case
  insensitive filesystems by reverting <xlocale.h> back to <sys/_locale.h>.


Bug Fixes
---------

- Fix select() on console in canonical mode.  Return after one line is
  completed, instead of when only one key is typed.

- Make console I/O functions thread-safe.

- Define missing MSG_EOR.  It's unsupported by the underlying Winsock
  layer so using it in send(2), sendto(2), or sendmsg(2) will return -1
  with errno set to EOPNOTSUPP and recvmsg(2) will never return it.