Remove duplicated elements from input to output [Insertion Sort]

// C Code

#include <assert.h>
#include <complex.h>
#include <ctype.h>
#include <errno.h>
#include <fenv.h>
#include <float.h>
#include <inttypes.h>
#include <iso646.h>
#include <limits.h>
#include <locale.h>
#include <math.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <tgmath.h>
#include <time.h>
#include <wchar.h>
#include <wctype.h>

void strings_fprintfln(FILE *f, char **s, int n, const char *fmt)
{
  strings_fprintf(f, s, n, fmt);
  fprintf(f, "\n");
}
void strings_printfln(char **s, int n, const char *fmt)
{
  strings_fprintfln(stdout, s, n, fmt);
}

char *str_dup(const char *s)
{
  char *result = (char *) malloc(strlen(s) + 1);
  strcpy(result, s);
  return result;
}

int strings_readwords(FILE *f, char **a)
{
  int result = 0;
  char word[MAX_LINE_LENGTH];
  while (fscanf(f, "%s", word) != EOF)
    a[result++] = str_dup(word);
  return result;
}

int strings_getwords(char **a)
{
  return strings_readwords(stdin, a);
}

//Insertion sort
void strings_sort_last(char **a, int n)
{
  int i = n-1;
  while (i > 0 && strcmp(a[i-1], a[i]) > 0)
  {
    strings_exchange(a, i-1, i);
    i--;
  }
}
void strings_isort(char **a, int n)
{
  for (int i = 2; i <= n; i++)
    strings_sort_last(a, i);
}

void test_stringsisort(void)
{
  char *a[1000];
  int n;
  while ((n = strings_getwords(a)) != 0)
  {
    strings_isort(a, n);
    strings_printfln(a, n, " ");
    //removeDuplicates(? , ?); *I NEED THIS!!!*
    freopen("CON", "r", stdin);
    printf("------\n");
  }
}

int main(void)//int argc, string argv[])
{
  test_stringsisort();
  return 0;
}

Bugh
Aure
Cure
Modew
Cure
Kire
Losa
Modew
Kurds

Aure
Bugh
Cure
Cure
Kire
Kurds
Losa
Modew
Modew

Aure
Bugh
Cure
Kire
Kurds
Losa
Modew