proxy.c now no longer refers to `cfg'. Instead, each of the three

proxy-indirection network functions (name_lookup, new_connection,
new_listener) takes a `const Config *' as an argument, and extracts
enough information from it before returning to handle that
particular network operation in accordance with the proxy settings
it specifies. This involved {win,ux}net.c due to a `const'
repercussion.

[originally from svn r2567]

proxy.h

@@ -79,6 +79,8 @@ struct Socket_proxy_tag {
     /* accepting */
     void *accepting_sock;
 
+    /* configuration, used to look up proxy settings */
+    Config cfg;
 };
 
 typedef struct Plug_proxy_tag * Proxy_Plug;