Your solution

• is not strict-safe, but that can be fixed with a my
• is not optimized away,
• doesn't have indentable directives.

The following doesn't suffer from those limitations:

0 && q{
  ...
};
[download]

0 && comment && q{
  ...
};
[download]

use constant _comment_ => 0;

_comment_ && q{
  ...
};
[download]