Pull up following revision(s) (requested by jmcneill in ticket #428):
external/bsd/nvi/dist/cl/cl_main.c: revision 1.9
When testing to see if a signal handler was previously installed in
h_winch, test sa_handler against all SIG_* actions defined in sys/signal.h
instead of just 0. Corrects an issue where vi crashes after a window is
resized.

(msaitoh)