OK

Sources of the very-very-very preliminary version of SemanticHighlight plugin are attached.
But be warned:
1.
The plugin crashes sometimes as I've already mentioned. I suspect that this happens when SH does highlighting on a control and simultaneously the user types some text to that control. I don't know whether there is some way to lock the control during highlighting process, but maybe you know

So please,
do not use the plugin in its present form while doing important things in C::B!2. If you change compile options of some target and/or project, SH doesn't notice those changes. It will when we add an event posted on such changes (EVT_PROJECT_TARGETS_MODIFIED is NOT posted on such changes though, in fact there is currently no event posted!).
3. There is no configuration panel yet.
4. On C::B startup, the GUI can be messed a little bit (wxExecute on EVT_EDITOR_ACTIVATED), but if you click on a boundary between panels everything returns to the correct layout.
5. Lines 301 and 302 of SemanticHighlight.cpp have to be adjusted according to your gcc configuration. Otherwise the plugin will work but some identifiers won't be highlighted correctly. These lines are needed in some gcc configurations as libclang doesn't include them in default search directories and then some fatal errors prevent libclang's parser to do entire job.
6. The plugin should work under Windows, but I didn't test it.
7. Please, check your compiler and linker options (libraries may have different names on your system).
Any questions and comments will be appreciated.
EDIT: I forgot: recall that the first parsing process may be quite long (about 4s on my machine).