git and mtime

Hi folks,

I'm using git to store some generated files, as well as their sources. (This is in the context of Debian package development, where entire upstream release tarballs are injected into an upstream branch, with Debian releases merging the upstream branch, and adding the Debian packaging files.)

The upstream release tarballs contains files such as
- yacc/lex code, and the corresponding generated sources
- Docbook/XML code, and corresponding HTML/PDF documentation

These are provided by upstream so that end users don't need these tools installed (particularly docbook, since the toolchain is so flaky on different systems). However, the fact that git isn't storing the mtime of the files confuses make, so it then tries to regenerate these (already up-to-date) files, and fails in the process since the tools aren't available.

Would it be possible for git to store the mtime of files in the tree?

This would make it possible to do this type of work in git, since it's currently a bit random as to whether it works or not. This only started when I upgraded to an amd64 architecture from powerpc32, I guess it's maybe using high-resolution timestamps.

Thanks, Roger

P.S. The repo I'm working on here is at
     git://git.debian.org/git/collab-maint/gutenprint.git