* GUILE-VERSION (GUILE_VERSION): Remove.
* Makefile.am (dist-hook): Depend on `gen-tarball-version'.
(BUILT_SOURCES): New variable.
($(top_srcdir)/.version, gen-tarball-version): New targets.
* cfg.mk (git-version-gen-tag-sed-script): New variable.
* configure.ac: Use `build-aux/git-version-gen' to generate the VERSION
argument of `AC_INIT'. Initialize Automake without `check-news'.
Define $GUILE_VERSION as an alias for $PACKAGE_VERSION.