* automake.in (%dist_common): Remove.

* automake.in (%dist_common): Remove.
(%configure_dist_common): Replace with...
($configure_dist_common): this.
(&generate_makefile): Read the user file before using
push_dist_common, as it sets DIST_COMMON, and read_am_file checks
that no variable is defined before it is run.
(&handle_texinfo): Don't handle DIST_COMMON, let your file do it.
(&dist_cmp): Rename as...
(&for_dist_common): this.
(&handle_dist): Don't handle DIST_COMMON, let `configure.am' do
it.
Adjust to $configure_dist_common.
* configure.am, texi-vers.am: Set DIST_COMMON.