Added the file descriptor set library (Cygwin bug)

Created by: nspaseski

I created a little chaos until I found out how to use the signatures ("signed-off by...") and I am sorry for that.

To copy the description from the other pull request: As explained in this thread: https://www.eclipse.org/forums/index.php/t/1075026/ On certain Cygwin configurations, it's impossible to compile without this line.