Create a directory named ``pup2'' under your home directory.
This directory must contain
- Makefile
- README
  Put your brief description of exercise in this file.
- main.c
  (Or you can copy it from Textbook on page 20, but change prototype of makeargv to
  #include "argvlib.h".)
- argvlib.c
  The C program contains your implementation of makeargv(). Your code should be thread-safe.
- argvlib.h
  Contains the prototype for makeargv().
When type ``make'' in your exercise directory, an executable named ``argvtest'' must be generated.
Due day, 3/11 00:05am

 
   The prototype of makeargv() is 
   int makeargv(const char *s, const char *delimiters, char ***argvp); 

   Example: 
     char *string = "this is a test";
     char *delimiters = " ";
     char **fields;
     int  numOfTokens;

     numOfTokens = makeargv(string, delimiters, &fields);

  The makeargv() separates the string into tokens according the delimiters 
  which are passed in second argument.
  makeargv() does not change the original string and delimiters and 
  will allocate memory for the third argument which is returned as the
  parsing result. In the example, after the invokation of makeargv(),
  fields[0] should be "this" and  fields[1] = "is" .....
  The return value is the number of tokes found.  The return value of 
  above example should be 4.  If any error were found, return -1.