rem: if (! spec && ! (spec = getenv ("BLOCK_SIZE")))
add: if (! spec && ! (spec = getenv ("BLOCK_SIZE")) && ! (spec = getenv ("BLOCKSIZE")))
context: humblock (char const *spec, uintmax_t *block_size, int *options){  int i;  int opts = 0;  if (! spec && ! (spec = getenv ("BLOCK_SIZE")))    *block_size = default_block_size ();  else    {      if (*spec == '\'')	{	  opts |= human_group_digits;	  spec++;	}      if (0 <= (i = ARGMATCH (spec, block_size_args, block_size_opts)))	{	  opts |= block_size_opts[i];	  *block_size = 1;	}      else	{	  char *ptr;	  strtol_error e = xstrtoumax (spec, &ptr, 0, block_size,				       "eEgGkKmMpPtTyYzZ0");	  if (e != LONGINT_OK)	    return e;	  if (*ptr)	    return LONGINT_INVALID_SUFFIX_CHAR;	  for (; ! ('0' <= *spec && *spec <= '9'); spec++)	    if (spec == ptr)	      {		opts |= human_SI;		if (ptr[-1] == 'B')		  opts |= human_B;		if (ptr[-1] != 'B' || ptr[-2] == 'i')		  opts |= human_base_1024;		break;	      }	}    }  *options = opts;  return LONGINT_OK;}