Make: only build something if the source's md5 checksum was changed

Question

Is it possible to tell make to only build a target if it\'s sources md5 checksum has changed (instead of the edit time)?

I\'m using make to

Answer 1

I found 3 ways: From simply

• Using temporary md5-files over an
• elegant but unreadable hack to
• patching GNU Make yourself

(from patchy but simple to clean but hard to realize)