redhat: Implement Makefile.dist

One of the nice things about the RHEL and ARK trees is that commands like 'make dist-configs' and 'make dist-help' can be executed from the top-level linux directory.

In the existing code, the makefile includes the top-level linux Makefile if the targets are not dist-* or distg-. Otherwise the commands are executed with the redhat/Makefile files. This is clunky and requires the inclusion of the makefile in .gitignore which causes problems when upstream modifies .gitignore.

A better approach is to include the code in a top-level Makefile.dist. This change can then be moved upstream for inclusion with a oneline patch to include Makefile.dist. Makefile.dist would not be included in the gitignore file because we want to track changes for the file in our own tree.

Move the makefile and Makefile.rhelver code into Makefile.dist, and include Makefile.dist from the top-level Makefile.

Signed-off-by: Prarit Bhargava prarit@redhat.com Cc: dzickus@redhat.com Cc: jforbes@redhat.com Cc: bcrocker@redhat.com