autoconf git and no host help2man

[Ross Burton]

Hi,

Should autoconf build from tarball without help2man?  I built a tarball 
of git master with 'make dist' but when I attempt to build that on 
another system it fails if help2man isn't present.  Shouldn't this be a 
requirement only for the git builds?  2.69 doesn't have this behaviour.

Cheers,
Ross