[Pas2js] Ignoring the UNIT dependencies

[Jean SUZINEAU]

I agree it doesn't make sense, and I don't know specifically for pas2js, 
but  usually specifying a unit in the uses clause can have an impact 
even if the code doesn't make any reference to the code of this unit, if 
the unit has an initialization part.

I think for example to the cthreads unit used in Linux for threads ( 
https://www.freepascal.org/docs-html/current/rtl/cthreads/index.html ), 
or the memory manager for memory allocation ( 
https://www.freepascal.org/docs-html/current/prog/progsu175.html ).