Using CMake's file(COPY ...) copies files only when CMake is run, which is only when a CMakeLists.txt or PlatformWin.cmake is touched. When a header is changed but no files are added or removed, it breaks the incremental build. Using xcopy as a build step solves this.
Created attachment 260088 [details] Patch
Comment on attachment 260088 [details] Patch r=me
r189055