Process: Increase FD_SETSIZE on Cygwin

The Single UNIX (R) Specification, Version 2 defines "FD_SETSIZE", but
does not specify the effects if it's (re)defined by an application.

Cygwin's newlib headers document that FD_SETSIZE may be defined
by the user [1] and should be >= NOFILE. [2]  Setting it to 16384
uses a value from Cygwin's poll() implementation. [3]

[1]: http://cygwin.com/cgi-bin/cvsweb.cgi/src/newlib/libc/include/sys/types.h?cvsroot=src
[2]: http://cygwin.com/cgi-bin/cvsweb.cgi/src/winsup/cygwin/include/sys/param.h?cvsroot=src
[3]: http://cygwin.com/cgi-bin/cvsweb.cgi/src/winsup/cygwin/poll.cc?cvsroot=src

Change-Id: Idc43fc28a398979da1e9289e1080a9fc1090c605