Yet more global-removal. The static variables in logging.c are now

absent, and also (I think) all the frontend request functions (such
as request_resize) take a context pointer, so that multiple windows
can be handled sensibly. I wouldn't swear to this, but I _think_
that only leaves the Unicode stuff as the last stubborn holdout.

[originally from svn r2147]

terminal.h

@@ -163,6 +163,10 @@ struct terminal_tag {
     void *resize_ctx;
 
     void *ldisc;
+
+    void *frontend;
+
+    void *logctx;
 };
 
 #define in_utf(term) ((term)->utf || line_codepage==CP_UTF8)