Fast way to select all AI types and difficulty levels

When setting up a multiplayer game with many AIs, it would be nice to
switch all AIs to the chosen one at once. Let's use RMB for
distributing the clicked slot's AI type and difficulty level to all
other AI slots.

src/multiint.cpp

@@ -2115,7 +2115,8 @@ void addPlayerBox(bool players)
 				{
 					if (NetPlay.isHost && !locked.ai)
 					{
-						sButInit.pTip = _("Click to change AI");
+						sButInit.style |= WBUT_SECONDARY;
+						sButInit.pTip = _("Click to change AI, right click to distribute choice");
 					}
 					else if (NetPlay.players[i].ai >= 0)
 					{
@@ -2833,7 +2834,27 @@ void WzMultiOptionTitleUI::processMultiopWidgets(UDWORD id)
 		else if (!NetPlay.players[player].allocated && !locked.ai && NetPlay.isHost
 		         && positionChooserUp < 0 && teamChooserUp < 0 && colourChooserUp < 0)
 		{
-			addAiChooser(player);
+			if (widgGetButtonKey_DEPRECATED(psWScreen) == WKEY_SECONDARY)
+			{
+				// Right clicking distributes selected AI's type and difficulty to all other AIs
+				for (int i = 0; i < MAX_PLAYERS; ++i)
+				{
+					// Don't change open/closed slots or humans
+					if (NetPlay.players[i].ai >= 0 && i != player && !isHumanPlayer(i))
+					{
+						NetPlay.players[i].ai = NetPlay.players[player].ai;
+						NetPlay.players[i].difficulty = NetPlay.players[player].difficulty;
+						sstrcpy(NetPlay.players[i].name, getAIName(player));
+						game.skDiff[i] = game.skDiff[player];
+						NETBroadcastPlayerInfo(i);
+					}
+				}
+				addPlayerBox(!ingame.bHostSetup || bHosted);
+			}
+			else
+			{
+				addAiChooser(player);
+			}
 		}
 	}