Thanks for all the work in improving static checking for Cygwin builds. 
I just now checked the attached patch into master, which I hope improves 
on it. I tested it on Fedora (both with and without window systems).

I had one problem with the recent changes, in that they suppressed all 
warnings about jumps over AUTO_STRING calls. That's pretty drastic, as 
the warnings are typically useful, so the attached patch reverts that. 
Can you let me know which call needs the warning suppressed in the 
Cygwin-specific code in the new master? I can suggest something which 
disables the warning just for that call.