Sort was including the trailing comma and getting the order wrong. (Specifically, it was comparing "sh," with "sha1sum," and putting sha1sum first in generated/newtoys.h so the binary search wasn't finding sha1sum. Alas, you can't feed separate beginning and ending delimiters to "sort -t". The fix is to copy the appropriate field out with sed, duplicate it at the start of the string where it's easy to compare, and then remove it again with a second sed after the sort.

/* vi: set sw=4 ts=4:
 *
 * sync.c - Write all pending data to disk.
 *
 * Copyright 2007 Rob Landley <rob@landley.net>
 *
 * Not in SUSv3.

USE_SYNC(NEWTOY(sync, NULL, TOYFLAG_BIN))

config SYNC
	bool "sync"
	default y
	help
	  usage: sync

	  Write pending cached data to disk (synchronize), blocking until done.
*/

#include "toys.h"

void sync_main(void)
{
	sync();
}