conditional enable use bytes for a whole module at compiletime?

[borisz]

Hi, I like to enable use bytes for a whole module, only if a condition is true. But since use bytes is out of scope, outside of the if, it has no effect. Sure I know I can wrap every function with the test, but I hope for a easy solution at the top of the module. Here is a example, the desired output is 3.

BEGIN {
package Y;
$VERSION = 0.1;
1;
package X;
if ( $Y::VERSION < 1 ) {
  # How to enable use bytes for the whole modue X?
  # with condition $Y::VERSION in mind?
  use bytes;
}
sub l{ return length shift } 

# large module follows

1;
}
package main;
no bytes;
$x = chr(3456);
print X::l($x);