PA (Parser arguments for C)

    My alternative to getopt by GNU since it does not provide
    the last flagname used, and as an exercise maybe...

    It's pretty simple to use, you can take a look into
    'demo.c' and test it by compiling it and running it

    An argument can be given as:
    -a      <argument>              by id
    --add   <argument>              by flagname
    --add=<argument>                unix-like

    If a flag does not take an argument but an argument
    is given it will be interpreted as a positional argument

    --does-not-take-arg <argument-dahhh> 
       \                       `~~~~~~~~~> this is given as an independent thing (pa_ret_pos_arg)
        `~~~~~~~~ id of this argument is given

    If a flag requires an argument but no argument is given
    it does not terminate the program, it will return `pa_ret_missed_arg`
    and it will be handled by the programmer as they want.

    In fact the only two errors which can terminate the program are:
      * Cannot allocate memory
      * pa_option structure is bad defined

    Juan Diego PM - Jan 30 2025