return 1;
static void gap_try(int x, int y, int *run, int *saw, int along_x) {	int n, m, i, xt, yt;	n = x + y * ntiles_x;	if (! tile_has_diff[n]) {		if (*saw) {			(*run)++;	/* extend the gap run. */		}		return;	}	if (! *saw || *run == 0 || *run > gaps_fill) {		*run = 0;		/* unacceptable run. */		*saw = 1;		return;	}	for (i=1; i <= *run; i++) {	/* iterate thru the run. */		if (along_x) {			xt = x - i;			yt = y;		} else {			xt = x;			yt = y - i;		}		m = xt + yt * ntiles_x;		if (tile_tried[m]) {	/* do not repeat tiles */			continue;		}		copy_tiles(xt, yt, 1);	}	*run = 0;	*saw = 1;}