[m-rev.] for review: Replace MD4 implementation with MD5.

[Zoltan Somogyi]

2021-06-03 15:31 GMT+10:00 "Peter Wang" <novalazy at gmail.com>:
> We used MD4 digests in the implementation of the `--track-flags'feature. While there is no particular need to change, IIRC the only
> reason I didn't use the more common MD5 algorithm is because I did not
> know of a small portable implementation at the time.

I approve of the idea. Given that that most of the diff consists of
external code, and the rest is trivial interface code, I don't think
any further review is needed.

The obvious question is: does this get a warning/error from gcc 11?

Zoltan.