When you check out a snapshot from the source code via Git, the build-system fails to work if you don't have the Git information (the .git dir) anymore. More specifically, it tries to use git-version-info which fails. It should still work thought and provide some fallback mechanism. This case happens for example in the Homebrew system on MacOSX which has an option to build the current trunk. That option will download the source from Git but when building the source, it doesn't include the .git directory.
You can set GIT_DESCRIBE_FOR_BUILD in your environment and that version will be used if you can't run 'git describe' in your build environment. Please feel free to continue commenting or to reopen the bug if you need further help.
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.