Bounce units to tiles where it can just exist if it cant "survive" in…

… any of the available tiles.

Fixes #931

server/unittools.cpp

@@ -1228,6 +1228,28 @@ void bounce_unit(struct unit *punit, bool verbose)
   }
   square_iterate_end;
 
+  if (count == 0) {
+    /* If no place unit can survive try the same with tiles the unit can just
+     * exist inspite of losing health or fuel*/
+    square_iterate(&(wld.map), punit_tile, DIST, ptile)
+    {
+      if (count >= ARRAY_SIZE(tiles)) {
+        break;
+      }
+
+      if (ptile == punit_tile) {
+        continue;
+      }
+
+      if (can_unit_exist_at_tile(&(wld.map), punit, ptile)
+          && !is_non_allied_city_tile(ptile, pplayer)
+          && !is_non_allied_unit_tile(ptile, pplayer)) {
+        tiles[count++] = ptile;
+      }
+    }
+    square_iterate_end;
+  }
+
   if (count > 0) {
     struct tile *ptile = tiles[fc_rand(count)];