Store information on version of external programs at the commit date?

While stumbling over this old thread, I noticed there is one thing I didn't wo开发者_开发问答rry about so far: external dependencies. Is there a smart¹ way to make git store some basic information on the current version of external applications used?

¹⁾ with smart I mean something more sophisticated than keeping manually track in a textfile everytime I remember having done such an update...

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Usually, IDE's will keep track of required external dependencies + version information for you (in the form of workspace and project files).

If that is not enough for you, you could have a look at git submodules which allows you to 'refer' to specific versions of external projects (which could be in git, svn, bzr or hg repositories through the use of git-svn, git-hg and so on)