This is the patch previously suggested by Pedro here:

https://sourceware.org/ml/gdb-patches/2015-09/msg00637.html

to fix a problem I ran into when testing on a remote Windows host via 
SSH without a terminal or job control.  As Pedro said, when typing 'q' 
in response to a pagination prompt, there's no possibility of a SIGINT 
so we can bypass the parts of quit() handling that are intended to 
intercept ^C instead.

I confirmed that this fixes the bogus quit message I observed previously 
on Windows host, and did full regression testing on Linux host for 
nios2-linux-gnu target.

OK to commit?

-Sandra