[clangd] parse error in macos headers

there's a small cosmetic issue with clangd when parsing macos system headers:
when looking at macos system headers, it seems that stdint.h is not properly traversed: standard c99 types are not defined. when opening stdint.h itself, the `#include_next` directive doesn't seem to be properly parsed, either.

this makes me wonder if the `#include_next` breaks the parsing also for "normal" system headers?