libmd: new recipe

[valgur]

Adds libmd: a message digest library from BSD. Required for the latest versions of libbsd.

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[conan-center-bot]

Conan v1 pipeline ✔️

All green in build 3 (cab668810e91151b5133688140560c5bd85aa982):

• libmd/1.1.0:
  All packages built successfully! (All logs)

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Conan v2 pipeline ✔️

Note: Conan v2 builds are now mandatory. Please read our discussion about it.

All green in build 3 (cab668810e91151b5133688140560c5bd85aa982):

• libmd/1.1.0:
  All packages built successfully! (All logs)

[AbrilRBS]

Nice! Thanks a lot for taking the time to create the recipe and your patience while it got reviewed, really appreciated

(There's something to be discussed about how to best prioritize your PRs, will let you know once I come up with something concrete)

Even though this looks good to me, I'm not approving just yet and will wait to find out if this PR needs more changes in light of the compilation errors that I reported in #21990 (review) - so that way if this bit is the faulty one somehow, we can avoid merging in that state and can fix it beforehand :)

[AbrilRBS]

Approving - the other PR does not fail due to this one :)