Otherwise, we end up propagating those dependencies into targets that
link against that library, which creates unnecessary link-time
dependencies.
Also included are changes to readd now missing dependencies to tools
that actually need them.
We previously put the generated headers in SOURCES, which did not mark
them as GENERATED (and did not produce a proper dependency).
This commit moves all generated headers into GENERATED_SOURCES, and
removes useless header SOURCES.
This is quite a radical change. The previous UI was very easy to add new
properties to (just add to the FooRole enum and it automatically
works), but not so nice to use: A ComboBox for selecting a property,
and then a box to edit that property's value. This makes it difficult
to compare different properties or edit multiple together without a lot
of back-and-forth.
This new design gives each property its own editing widgets, with those
categorized into several tabs. To try and avoid increasing the
maintenance burden for this, the UI is generated from the
`windows_tab`, `widgets_tab` and `syntax_highlighting_tab` variables,
which are basically just lists of which properties go in that tab. One
of the `FooProperty.gml` files is loaded to create each property's
widgets.
