You're confusing the GCC version with the MinGW version (can't blame you, it is confusing); your MinGW version is probably 5.x. MinGW 6.0 ships GCC 8.x or 9.1 and comes with the necessary headers.
You can also try copying the missing headers from a wine build to the include directory, although I'm not sure if that works.
Nothing extracted yet.
Hi, I got the
dxgi1_4.h: No such file or directoryusing mingw64 6.3 and meson 0.5