Note, the Unix build only identifies itself like that if there is a working copy of hg on $PATH at configure time.  If not, the version string also silently defaults to "default".  That requirement creates a bit of a problem for the OS X installer build script since hg is not currently shipped with OS X and the build script goes to some lengths to ensure that the build environment is not contaminated with non-system components, including setting PATH to standard system values.  It might also be an issue for some other Unix platform builds.  My preference would be to add an AC_PATH_PROG check or some such to configure.in to be able to specify an HG environment variable rather than having to open up PATH.  Comments?