[libcxx-commits] [libcxx] [libcxx] Fix include directory order (PR #65859)

[Mark de Wever via libcxx-commits]

mordante wrote:

Can you add this part 
"It's important that the arch directory be included first so that
its header files which interpose on the default include dir
be included instead of the default ones."

as comment in the code too? 

https://github.com/llvm/llvm-project/pull/65859