c607ead4b7
This commit moves generated `RNA_blender.h`, `RNA_prototype.h` and `RNA_blender_cpp.h` headers to become C++ header files. It also removes the now useless `RNA_EXTERN_C` defines, and just directly use the `extern` keyword. We do not need anymore `extern "C"` declarations here. Pull Request: https://projects.blender.org/blender/blender/pulls/124469