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.
compiler/md5.m:
compiler/Mercury.options:
Add implementation of MD5 digest algorithm.
The C code is public domain code, and apparently widely used.
compiler/md4.m:
Delete this module.
compiler/libs.m:
Include new module and delete old module.
compiler/make.m:
Calculate MD5 digest for `.track_flags' files instead of MD4.