Compare every single tag with a list of valid tags. This prevents broken
releases which occurred whenever someone made a typo on the command
line:

    $ ./archrelease community i686
    ==> ERROR: archrelease: Invalid tag: "community" (use -f to force release)

Since the list is used in the ZSH completion as well, break it out to a
separate file and move it to "lib/". Also, add a command line parameter
to allow for releasing to an unknown repository when necessary.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>
Signed-off-by: Pierre Schmitz <pierre@archlinux.de>

These tags make no sense. Remove them from our valid tag array that is
used for tab completion.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>
Signed-off-by: Pierre Schmitz <pierre@archlinux.de>

This build system overhaul allows for adding (define-style) macros to
our scripts. All source files are now suffixed with ".in" to clarify
that they might contain unprocessed defines. The Makefile provides a new
rule to preprocess source files and generate proper output scripts.

Also, add a "@pkgdatadir@" define (as used in GNU Autotools) and use it
instead of hardcoded paths to "/usr/share/devtools" everywhere. We
missed this when adding PREFIX support to the build system in commit
35fc83ce.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>

Make use of _devtools_completions_all_packages() instead of using
_devtools_completions_installed_packages(). The latter was removed
during an earlier review of the patch adding ZSH completion (now
6350ec04 in master) but we forgot to change two references.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>
Signed-off-by: Pierre Schmitz <pierre@archlinux.de>

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>
Signed-off-by: Pierre Schmitz <pierre@archlinux.de>