This function gets a file name, which is either absolute or relative to the current working directory and another file name which is absolute or relative to the first one.
The return value of the function is a file name which is either absolute or relative to the current woring directory.
The return value is dynamically allocated and is to be release by the caller.
The allocation function is taken from the class function and the segment is
char *reader_RelateFile(pReadObject pRo,