+proxy authentication
+
+ Allow RSYNC_PROXY to be http://user:pass@proxy.foo:3128/, and do
+ HTTP Basic Proxy-Authentication.
+
+ Multiple schemes are possible, up to and including the insanity that
+ is NTLM, but Basic probably covers most cases.
+
+SOCKS
+
+ Add --with-socks, and then perhaps a command-line option to put them
+ on or off. This might be more reliable than LD_PRELOAD hacks.
+