struct arg_and_data_s
{
  struct arg_and_data_s *next;
  gpgme_data_t data;  /* If this is not NULL, use arg below.  */
  int *arg_locp;   /* Write back the argv idx of this argument when
		      building command line to this location.  */
  int inbound;     /* True if this is used for reading from gpg.  */
  int dup_to;
  int print_fd;    /* Print the fd number and not the special form of it.  */
  char arg[];      /* Used if data above is not used.  */
};

t-fam.c: In function 'main':
t-fam.c:34:14: warning: array subscript 'struct arg_and_data_s[0]' is partly outside array bounds of 'unsigned char[22]' [-Warray-bounds]
   34 |   aad0->next = NULL;
      |              ^
t-fam.c:30:10: note: referencing an object of size 22 allocated by 'malloc'
   30 |   aad0 = malloc (offsetof (struct arg_and_data_s, arg) + 2);
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
t-fam.c:35:13: warning: array subscript 'struct arg_and_data_s[0]' is partly outside array bounds of 'unsigned char[22]' [-Warray-bounds]
   35 |   aad0->len = 2;
      |   ~~~~~~~~~~^~~
t-fam.c:30:10: note: referencing an object of size 22 allocated by 'malloc'
   30 |   aad0 = malloc (offsetof (struct arg_and_data_s, arg) + 2);
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
t-fam.c:36:15: warning: array subscript 'struct arg_and_data_s[0]' is partly outside array bounds of 'unsigned char[22]' [-Warray-bounds]
   36 |   aad0->flags = 0;
      |   ~~~~~~~~~~~~^~~
t-fam.c:30:10: note: referencing an object of size 22 allocated by 'malloc'
   30 |   aad0 = malloc (offsetof (struct arg_and_data_s, arg) + 2);
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
t-fam.c:37:18: warning: array subscript 'struct arg_and_data_s[0]' is partly outside array bounds of 'unsigned char[22]' [-Warray-bounds]
   37 |   aad0->print_fd = fd;
      |   ~~~~~~~~~~~~~~~^~~~
t-fam.c:30:10: note: referencing an object of size 22 allocated by 'malloc'
   30 |   aad0 = malloc (offsetof (struct arg_and_data_s, arg) + 2);
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~