build2 VS embedded-graphics

Yes, this is a common stumbling block for users with the CMake background. The underlying reason is that build2 is a "multi-repo first" build system while CMake is "mono-repo first" (or perhaps even "mono-repo only"; I don't think there were repositories as we know them when Autotools was designed ;-)). In particular, in build2 it's common to build multiple independent projects/repositories in a shared build configuration. Putting this build configuration as a subdirectory of source directory of one of them would be strange. You can read more on this in this issue: https://github.com/build2/build2/issues/187

build2 can generate Clang compilation database (currently indirectly): https://github.com/build2/build2/issues/96 I believe quite a few IDEs (including CLion) can work off that.

Yes, please, that would be very helpful: https://github.com/build2/build2/issues

Even if one used embedded-graphics, which would't require a line buffer, 8k is probably not enough RAM for the stack of a non-trivial Rust program. At least my even fairly simple RTIC programs that run fine in the 160k of a Feather M4 do not run at all in the 32k of a Feather M0.

I rewrote the font subsystem of U8g2 in pure Rust, introducing a large number of fonts to embedded-graphics.

Another project I've used is embedded-graphics which is useful if your target has more limited resources: https://github.com/embedded-graphics/embedded-graphics

We use it a bit for https://github.com/embedded-graphics/embedded-graphics and I have to say I love it. It's just the right balance between configuration variables/constants and "a folder full of bash scripts". I highly recommend giving Just a try.