find -size <number-without-suffix> not POSIX

[stephane-chazelas]

Per POSIX

find . -size n

is meant to return the files whose size rounded up to an integer number of 512-byte units is 1.

For instance, find . -size 1 is meant to report the files whose size ranges from 1 to 512 bytes (the ones that would typically occupy one sector of disk space in the olden days).

But for toybox (and busybox, which shares the same non-conformance), it only reports files whose size is exactly 512.

There are similar problems for find . -size +n and find . -size -n.

Like for the test utility (https://github.com/landley/toybox/issues/498), there's also the separate problem that find . -size 010c finds the files of size 8 instead of 10.

Note the behaviour when using suffixes other than c is fine as out of the POSIX scope and is aligned with most other implementations that support those or some of those suffixes (except GNU find).

See https://unix.stackexchange.com/questions/774817/what-are-the-file-size-options-for-find-size-command/774840#774840 for more of the gory details including comparison with other implementations.