undefined reference to `crypte'

Je suis en utilisant le code ci-dessous que j'ai trouvé quelque part sur le net et j'obtiens une erreur lorsque je tente de le construire. La compilation est ok.

Voici l'erreur:

/tmp/ccCnp11F.o: In function `main':

crypt.c:(.text+0xf1): undefined reference to `crypt'

collect2: ld returned 1 exit status

et voici le code:

#include <stdio.h>
 #include <time.h>
 #include <unistd.h>
 #include <crypt.h>

 int main()
 {
   unsigned long seed[2];
   char salt[] = "$1$........";
   const char *const seedchars =
     "./0123456789ABCDEFGHIJKLMNOPQRST"
     "UVWXYZabcdefghijklmnopqrstuvwxyz";
   char *password;
   int i;

   /* Generate a (not very) random seed.
      You should do it better than this... */
   seed[0] = time(NULL);
   seed[1] = getpid() ^ (seed[0] >> 14 & 0x30000);

   /* Turn it into printable characters from `seedchars'. */
   for (i = 0; i < 8; i++)
     salt[3+i] = seedchars[(seed[i/5] >> (i%5)*6) & 0x3f];

   /* Read in the user's password and encrypt it. */
   password = crypt(getpass("Password:"), salt);

   /* Print the results. */
   puts(password);
   return 0;
 }