Separate out Chunks-related code, "fix" collisions to be less broken

src/math.zig

@@ -73,3 +73,11 @@ pub inline fn mulFracFrac(a: i32, b: i32) i32 {
     const b_wide: i64 = b;
     return .{ .vector = @intCast(@divFloor(a_wide * b_wide + rounding_bias, denominator)) };
 }
+
+pub inline fn wideMulDivFloor(a: i32, mul: i32, div: i32) i32 {
+    return @intCast(@divFloor(@as(i64, a) * @as(i64, mul), div));
+}
+
+pub inline fn wideMulDivCeil(a: i32, mul: i32, div: i32) i32 {
+    return @intCast(@divFloor(@as(i64, a) * @as(i64, mul) + @as(i64, div) - 1, div));
+}