[iagno] Fix AI regression.

[Arnaud B. <arnaudb src gnome org>]

commit 675ca91399a95fb4ef3a5747841b6426b80bc42c
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Fri Mar 29 15:04:19 2019 +0100

    Fix AI regression.

 src/computer-player.vala | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/src/computer-player.vala b/src/computer-player.vala
index 760be13..92e4991 100644
--- a/src/computer-player.vala
+++ b/src/computer-player.vala
@@ -236,7 +236,8 @@ private class ComputerPlayer : Object
     {
         /* End of the game, return a near-infinite evaluation */
         if (g.is_complete)
-            return g.n_current_tiles > g.n_opponent_tiles ? POSITIVE_INFINITY - g.n_opponent_tiles : 
NEGATIVE_INFINITY + g.n_current_tiles;
+            return g.n_current_tiles > g.n_opponent_tiles ? POSITIVE_INFINITY - (int) g.n_opponent_tiles
+                                                          : NEGATIVE_INFINITY + (int) g.n_current_tiles;
 
         /* Checking move_pending here is optional. It helps avoid a long unnecessary search
          * if the move has been cancelled, but is expensive because it requires taking a mutex. */
@@ -318,7 +319,7 @@ private class ComputerPlayer : Object
 
     private static int calculate_heuristic (Game g, ref uint8 difficulty_level)
     {
-        int tile_difference = g.n_current_tiles - g.n_opponent_tiles;
+        int tile_difference = (int) g.n_current_tiles - (int) g.n_opponent_tiles;
 
         /* Try to lose */
         if (difficulty_level == 1)