By default, export MD5 digest of real name associated with an avatar

This enables Avatar displays on real-name-only networks without leaking
real names into the SYNCDATA sub.

If the -realnames option is used, the unobscured full real names are
exported (as before).

If the (new) -aliasonly option is used, even the MD5 digest of users'
real names is left out.

exec/avatars.js

@@ -366,8 +366,12 @@ function export_users(msgbase, realnames, all)
 				if(!list.disabled)
 					list.disabled = [];
 				list.disabled.push(u.alias);
-				if(realnames)
-					list.disabled.push(u.name);
+				if(u.name != u.alias) {
+					if(realnames)
+						list.disabled.push(u.name);
+					else if(realnames !== false)
+						list.disabled.push("md5:" + md5_calc(u.name));
+				}
 			} else {
 				if(!lib.is_enabled(avatar))	{
 					alert("Invalid avatar for user #" + n);
@@ -378,8 +382,12 @@ function export_users(msgbase, realnames, all)
 				if(!list[data])
 					list[data] = [];
 				list[data].push(u.alias);
-				if(realnames && u.name != u.alias)
-					list[data].push(u.name);
+				if(u.name != u.alias) {
+					if(realnames)
+						list[data].push(u.name);
+					else if(realnames !== false)
+						list[data].push("md5:" + md5_calc(u.name));
+				}
 			}
 			avatar.last_exported = new Date();
 			avatar.export_count++;
@@ -541,7 +549,7 @@ function main()
 	var cmd;
 	var i;
 	var offset;
-	var realnames = false;
+	var realnames;
 	var ptr;
 	var limit;
 	var all;
@@ -571,6 +579,9 @@ function main()
 			case '-realnames':
 				realnames = true;
 				break;
+			case '-aliasonly':
+				realnames = false;
+				break;
 			case "-ptr":
 				ptr = val;
 				break;