island_try(x, y, x+1, y, &run);
ct = island_try(x, y, x+1, y, &run); if (ct < 0) return ct;
static int grow_islands(void) {	int x, y, n, run;	int diffs = 0;	/*	 * n.b. the way we scan here should keep an extension going,	 * and so also fill in gaps effectively...	 */	/* left to right: */	for (y=0; y < ntiles_y; y++) {		run = 0;		for (x=0; x <= ntiles_x - 2; x++) {			island_try(x, y, x+1, y, &run);		}	}	/* right to left: */	for (y=0; y < ntiles_y; y++) {		run = 0;		for (x = ntiles_x - 1; x >= 1; x--) {			island_try(x, y, x-1, y, &run);		}	}	for (n=0; n < ntiles; n++) {		if (tile_has_diff[n]) {			diffs++;		}	}	return diffs;}