-Idirectory
            may  be  used  in  conjunction  with -P to tell the C preprocessor
            where to look for include  files.   By  default  /usr/include  and
            /usr/lib/perl are searched.

       -P   causes your script to be run through  the  C  preprocessor  before
            compilation  by  perl.   (Since  both  comments and cpp directives
            begin with the # character, you  should  avoid  starting  comments
            with  any  words  recognized  by  the C preprocessor such as "if",
            "else" or "define".)