If we're sharing buffers, we only want to share trivial structures
as anything else could potentially share internal pointers, which
most likely is going to cause problems due to different address
spaces.
Fix the GUI::SystemTheme structure, which was not trivial, which
is now caught at compile time.
Fixes#3650
Indexed bitmaps used to allocate four times the required amount of memory.
Also, we should acknowledge that the underlying data is not always RGBA32,
and instead cast it only when the true type is known.
This commit moves the clipboard from WindowServer into a new Clipboard
service program. Clipboard runs as the unprivileged "clipboard" user
and with a much tighter pledge than WindowServer.
To keep things working as before, all GUI::Application users now make
a connection to Clipboard after making the connection to WindowServer.
It could be interesting to connect to Clipboard on demand, but right
now that would necessitate expanding every GUI app's pledge to include
"unix" and also unveiling the clipboard portal, which I prefer not to.
This feels a lot more consistent and Unixy:
create_shared_buffer() => shbuf_create()
share_buffer_with() => shbuf_allow_pid()
share_buffer_globally() => shbuf_allow_all()
get_shared_buffer() => shbuf_get()
release_shared_buffer() => shbuf_release()
seal_shared_buffer() => shbuf_seal()
get_shared_buffer_size() => shbuf_get_size()
Also, "shared_buffer_id" is shortened to "shbuf_id" all around.
