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chgserver: catch Abort while parsing early args to shut down cleanly _loadnewui() calls dispatcher functions, which may raise Abort if unparsable arguments are passed in. The server should catch such errors and translate them to the "exit 255" instruction so the client can finish the IPC session cleanly. Spotted while porting the chg client to Rust.

chg: upgrade client to use "setumask2" command No compatibility code is added to the client side, since it's unlikely for new client to communicate with the old server.

chgserver: add "setumask2" command which uses correct message frame The first 4 bytes should be a length field, not a value. Spotted while porting chg functions to the Rust one.

packaging: "make deb" no longer fails Release 4.7 rationalized the layout of the build scripts. Unfortunately, while "make docker-ubuntu-*" and "make docker-debian-*" worked as expected, "make deb" was broken. Before this change "make deb" was failing with the following error: You are not inside a Mercurial repository! Or, after the latest changes: You are inside <fullpath>, which is not the root of a Mercurial repository Moreover, when "make deb" failed, the cleanup routine deleted the wrong directory (contrib/packaging/debian instead of <reporoot>/debian) resulting in a corrupted working copy that needed to be hg revert-ed. After this change the docker targets continue to work, and the deb one is able to finish.

packaging: cleanup() did not read the value of $CLEANUP When the original author put CLEANUP in a conditional statement he was probably willing to use it to control the "if". This change tries to restore that behaviour: the "rm" clause is triggered if and only if CLEANUP is defined and not empty.