* src/cuirass/remote.scm (zmq-message-receive*): New procedure.
* src/cuirass/remote-server.scm (start-fetch-worker, zmq-start-proxy): Use it.

* src/cuirass/remote-server.scm (remote-server): Move the locale setup to the
publish thread.
* src/cuirass/remote-worker.scm (remote-worker): Ditto.
* src/cuirass/remote.scm (publish-server): Set the locale.

* src/cuirass/remote.scm (zmq-server-info, zmq-worker-request-info-message):
New procedures.
* src/cuirass/remote-server.scm (%log-port, %publish-port): New parameters.
(read-worker-exp): Handle 'worker-request-info message.
(remote-server): Set the new parameters.
* src/cuirass/remote-worker.scm (start-worker): Rename "server" argument. Send
a 'worker-request-info message to discover the server log port and publish
port.
(remote-worker): Adapt it.

* src/cuirass/remote.scm (swallow-zlib-error): New macro.
(send-log): Use it.

* src/sql/upgrade-2.sql: New file.
* Makefile.am (dist_sql_DATA): Add it.
* src/schema.sql (Workers): Add "machine field".
* src/cuirass/database.scm (db-get-builds): Return "worker" field.
(db-add-worker): Honor new "machine" field.
(db-get-workers): Ditto.
* src/cuirass/remote-worker.scm (remote-worker): Adapt it.
* src/cuirass/remote.scm (<worker>)[machine]: New field.
(worker-machine): New procedure.
(worker->sexp, sexp->worker): Adapt accordingly.
(generate-worker-name): Ditto.
* tests/database.scm (%dummy-worker): Add "machine" field.

* src/cuirass/remote-server.scm (remote-server): Have stdout/stderr
line-buffered.
* src/cuirass/remote-worker.scm (remote-worker): Ditto.
* src/cuirass/remote.scm (publish-server): Discard publish logs.

Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>

* src/cuirass/remote.scm: New file.
* src/cuirass/remote-server.scm: New file.
* src/cuirass/remote-worker.scm: New file.
* bin/remote-server.in: New file.
* bin/remote-worker.in: New file.
* Makefile.am (bin_SCRIPTS): Add new binaries,
(dist_pkgmodule_DATA): add new files,
(EXTRA_DIST): add new binaries,
(bin/remote-server, bin/remote-worker): new targets.
* .gitignore: Add new binaries.
* bin/cuirass.in (%options): Add "--build-remote" option,
(show-help): document it,
(main): honor it.
* src/cuirass/base.scm (with-build-offload-thread): New macro,
(%build-remote?, %build-offload-channel): new parameters,
(make-build-offload-thread): new procedure,
(build-derivations/offload): new procedure,
(restart-builds): use it to offload builds when %build-remote? is set,
(build-packages): ditto.