Use C++-style casts (#1576)

src/gfx/reverse.cpp

@@ -164,7 +164,7 @@ void reverse() {
 		// Pick the smallest width that will result in a landscape-aspect rectangular image.
 		// Thus a prime number of tiles will result in a horizontal row.
 		// This avoids redundancy with `-r 1` which results in a vertical column.
-		width = (size_t)ceil(sqrt(mapSize));
+		width = static_cast<size_t>(ceil(sqrt(mapSize)));
 		for (; width < mapSize; ++width) {
 			if (mapSize % width == 0)
 				break;