If I use termios(3) to set VTIME and VMIN to values greater than zero for
a serial port, I can no longer interrupt a read(2) against the descriptor
with SIGALRM. Replacing read(2) with nanosleep(2) yields EINTR as
expected. Not setting VTIME and VMIN, read(2) yields EINTR as desired.
Test program and cygcheck output attached. Could be this is intended
behavior. It seems more likely that this is a bug in the driver for my
USB-to-serial adapter. Cygwin 1.7.17 snapshot 2012-10-16.

-- 
J. L. Sloan          Digital Aggregates Corp.
+1 303 940 9064 (O)  3440 Youngfield St. #209
+1 303 489 5178 (M)  Wheat Ridge CO 80033 USA
jsloan@diag.com      http://www.diag.com