build: Change dependencies to match Debian packages

HACKING.md

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+Hacking
+=======
+
+This document describes the standards for modifying and maintaining the *squeekboard* project.
+
+Testing
+-------
+
+Most common testing is done in CI. Occasionally, and for each release, do perform manual tests to make sure that
+
+- the application draws correctly
+- it shows when relevant
+- it changes layouts
+- it changes levels
+
+Testing with an application:
+
+```
+python3 tests/entry.py
+```
+
+Testing visibility:
+
+```
+$ busctl call --user sm.puri.OSK0 /sm/puri/OSK0 sm.puri.OSK0 SetVisible b true
+$ busctl call --user sm.puri.OSK0 /sm/puri/OSK0 sm.puri.OSK0 SetVisible b false
+```
+
+Testing layouts:
+
+```
+$ gsettings set org.gnome.desktop.input-sources sources "[('xkb', 'us'), ('xkb', 'ua')]"
+$ gsettings set org.gnome.desktop.input-sources current 1
+```
+
+Maintenance
+-----------
+
+Squeekboard uses Rust & Cargo for some of its dependencies.
+
+Use the `cargo.sh` script for maintaining the Cargo part of the build. The script takes the usual Cargo commands, after the first 2 positionsl arguments: source directory, and output artifact. So, `cargo test` becomes:
+
+```
+cd build_dir
+sh /source_path/cargo.sh /source_path '' test
+```
+
+### Cargo dependencies
+
+Dependencies must be specified in `Cargo.toml` with 2 numbers: "major.minor". Since bugfix version number is meant to not affect the interface, this allows for safe updates.
+
+`Cargo.lock` is used for remembering the revisions of all Rust dependencies. It should be updated often, preferably with each bugfix revision, and in a commit on its own:
+
+```
+cd build_dir
+sh /source_path/cargo.sh /source_path '' update
+ninja test
+```