The unit tag describes one input file for the package. This tag corresponds to the --input
command-line option.
The tag has 2 attributes:
     
- 
file 
- The file tag contains the file name. This attribute is mandatory.
     
- 
options 
- The options attribute is optional, and specifies any options that must be passed on
     to the parser when parsing the input file.
Example:
                                                                            
                                                                            
<unit file="cthreads.pp" options="-S2"/>