It’s possible. Needs the first errors to right click open a file of imports. Then add the juce modules (in the plugin dir), system includes, apparently freetype2 (for ft2build.h). Just edit the includes dot file in the editor or Kate. Add a run configuration to launch the built standalone with a depends on make standalone. OK.
Also try “Scope: Project” in the “Parser” tab of the “Problems” tab to get rid of the “errors” (Scope: file).
But in the end it has inconsistent GUI launching.
So I went with Zed with clang LSP. Oh, and erm, the <> instead of "” on those #include statements are for system/global libraries. Quotes for project libraries, because not everything should be on the library path, and a .clang YAML file for includes seems the way to go. Now to suppress the 4 project errors due to the wrong style of include brackets. Because I’m sure Projucer will just put new ones in there some day, and I don’t like such minor pedantism when a build happens.
A make clean and bear – make in the LinuxMakefile directory, and link the resulting .json into the project root. Errors gone. Lovely.