The two main changes, done together in this commit, are:
* Eliminating most instances of `aux_source_directory()`, replacing
them with explicit file listings; and
* Moving these file listings into respective subdirectories by
representing respective nextpnr components as interface libraries.
In addition, the GUI CMake script tree was simplified since it had
a lot of unused/redundant code.
The `aux_source_directory()` command is not recommended for use by
CMake itself because it misses dependency changes when adding/removing
files, and consequently causes build failures requiring a clean rebuild.
This commit does not touch anything related to architectures/families,
which are very complex and redundant all on their own.
* Items such as LUT, DFF, MUX, ALU, IOB are displayed;
* Local wires, 1-2-4-8 wires are displayed;
* The clock spines, taps and branches are displayed with some caveats.
For now, you can not create a project in the GUI because of possible
conflict with another PR (about GW1NR-9C support), but you can specify
the board in the command line and load .JSON and .CST in the GUI.
Although ALUs are displayed, but the CIN and COUT wires are not. This is
still an unsolved problem.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
