well-written, since my brain is largely absent today.
[originally from svn r4945]
\e{don't} care about. In particular, we expect PuTTY to be compiled
on 32-bit architectures \e{or bigger}; so it's safe to assume that
\c{int} is at least 32 bits wide, not just the 16 you are guaranteed
-by ANSI C.)
+by ANSI C. Similarly, we assume that the execution character encoding
+is a superset of the printable characters of ASCII, though we don't
+assume the numeric values of control characters, particularly \cw{'\n'}
+and \cw{'\r'}.)
\H{udp-multi-backend} Multiple backends treated equally