WINCHAIN - a framework allowing multiple processors between core and winport

This is the code I built trying to figure out the large window size issue.
It completely compiles out if not needed (see -DWINCHAIN in hints/macos10.7)
and except for one call during setup has zero overhead if compiled in and
not used.  See window.doc for more info.

Defs for UNUSED parms.  I know this has been controversial, so use is isolated
to the chain code and windows.c (where it shouldn't be intrusive and saves about
50 warnings).

Hints file for 10.7, but the build process still needs to be migrated from
the branch.

src/options.c

@@ -400,6 +400,9 @@ static struct Comp_Opt
 	{ "windowcolors",  "the foreground/background colors of windows",	/*WC*/
 						80, DISP_IN_GAME },
 	{ "windowtype", "windowing system to use", WINTYPELEN, DISP_IN_GAME },
+#ifdef WINCHAIN
+	{ "windowchain", "window processor to use", WINTYPELEN, SET_IN_SYS },
+#endif
 #ifdef BACKWARD_COMPAT
 	{"DECgraphics", "load DECGraphics display symbols", 70, SET_IN_FILE},
 	{"IBMgraphics", "load IBMGraphics display symbols", 70, SET_IN_FILE},
@@ -2394,6 +2397,20 @@ goodfruit:
 	    }
 	    return;
 	}
+#ifdef WINCHAIN
+	fullname = "windowchain";
+	if (match_optname(opts, fullname, 3, TRUE)) {
+	    if (negated) {
+		bad_negation(fullname, FALSE);
+		return;
+	    } else if ((op = string_for_env_opt(fullname, opts, FALSE)) != 0) {
+		char buf[WINTYPELEN];
+		nmcpy(buf, op, WINTYPELEN);
+		addto_windowchain(buf);
+	    }
+	    return;
+	}
+#endif
 
 	/* WINCAP
 	 * setting window colors