Build bug report: 'make check' needs sparse, but configure doesn't check it

When you build git-1.6.0.2 and 'make check', it tries to run sparse and fails if sparse is not there. But the configure script does not check sparse is installed.

I suggest that 'make check' skip the sparse tests if sparse is not there. As I understand it, they are really more for the developers to get a report of possible errors in the source code and not to test that the built executables work, so it would not be dangerous to just skip running those tests for ordinary users who don't have the tool.

Alternatively, if running sparse is really important for a thorough 'make check', the configure script should check for it and warn you to install it.