Pre-processor should remove empty lines
When using complicated logic in the pre-processor language, one can often end up with files full of thousands of empty lines. This is both because empty lines are necessary to make pre-processor code readable, and because of the need to have empty lines at the end of .mod files that finish with e.g. an @#endfor .
It would be helpful if the pre-processor removed empty lines in the generated -macroexp.mod.