More options in a Linux command and compilation error - c

Question

I am trying to add as option in the command $ printenv the command date . e.g. if you try to run $ printenv -d it should return the date output.
I have the src code from the link ftp://ftp.ntua.gr/pub/gnu/coreutils/coreutils-8.23.tar.xz that contains all the coreutils in a linux distribution.
I have already change the source code of src/printenv.c (this file is in the coreutils.tar file). But what is my next move ?
I can not compile it with gcc printenv.c
Compile error: fatal error: config.h: No such file or directory
compilation terminated.
Should I make the makefiles/configs etc and install it manually? How?
I post my changed code (printenv.c)
/* printenv -- print all or part of environment
Copyright (C) 1989-2014 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Usage: printenv [variable...]
If no arguments are given, print the entire environment.
If one or more variable names are given, print the value of
each one that is set, and nothing for ones that are not set.
Exit status:
0 if all variables specified were found
1 if not
2 if some other error occurred
David MacKenzie and Richard Mlynarik */
#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include <getopt.h>
#include "system.h"
/* Exit status for syntax errors, etc. */
enum { PRINTENV_FAILURE = 2 };
/* The official name of this program (e.g., no 'g' prefix). */
#define PROGRAM_NAME "printenv"
#define AUTHORS \
proper_name ("David MacKenzie"), \
proper_name ("Richard Mlynarik")
static struct option const longopts[] =
{
{"null", no_argument, NULL, '0'},
{"date", required_argument, NULL, 'd'},
{GETOPT_HELP_OPTION_DECL},
{GETOPT_VERSION_OPTION_DECL},
{NULL, 0, NULL, 0}
};
/* Forward declarations. */
static void dateMachine (void);
void
usage (int status)
{
if (status != EXIT_SUCCESS)
emit_try_help ();
else
{
printf (_("\
Usage: %s [OPTION]... [VARIABLE]...\n\
Print the values of the specified environment VARIABLE(s).\n\
If no VARIABLE is specified, print name and value pairs for them all.\n\
\n\
"),
program_name);
fputs (_("\
-0, --null end each output line with NUL, not newline\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
emit_ancillary_info ();
}
exit (status);
}
int
main (int argc, char **argv)
{
char **env;
char *ep, *ap;
int i;
bool ok;
int optc;
bool opt_nul_terminate_output = false;
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
initialize_exit_failure (PRINTENV_FAILURE);
atexit (close_stdout);
while ((optc = getopt_long (argc, argv, "+iu:0d", longopts, NULL)) != -1)
{
switch (optc)
{
case '0':
opt_nul_terminate_output = true;
break;
case 'd':
dateMachine ();
break;
case_GETOPT_HELP_CHAR;
case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
default:
usage (PRINTENV_FAILURE);
}
}
if (optind >= argc)
{
for (env = environ; *env != NULL; ++env)
printf ("%s%c", *env, opt_nul_terminate_output ? '\0' : '\n');
ok = true;
}
else
{
int matches = 0;
for (i = optind; i < argc; ++i)
{
bool matched = false;
/* 'printenv a=b' is silent, even if 'a=b=c' is in environ. */
if (strchr (argv[i], '='))
continue;
for (env = environ; *env; ++env)
{
ep = *env;
ap = argv[i];
while (*ep != '\0' && *ap != '\0' && *ep++ == *ap++)
{
if (*ep == '=' && *ap == '\0')
{
printf ("%s%c", ep + 1,
opt_nul_terminate_output ? '\0' : '\n');
matched = true;
break;
}
}
}
matches += matched;
}
ok = (matches == argc - optind);
}
exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
}
static void
dateMachine (void)
{
system(date);
}

Answer 1

If you google "printenv.c" You'll find several versions of just that file, that you can compile and run with minimal jiggery-pokery.
Example: "http://www.opensource.apple.com/source/shell_cmds/shell_cmds-170/printenv/printenv.c"

Answer 2

./configure && make (without sudo). It compiles every .c program locally.
It compiles only the .c files that have been changed, due to datestamp.