Does not compile with LLVM/clang about efivar

[amagnasco]

same on arch 'armv7h'

[vathpela]

Well, we no longer use __builtin_va_arg_pack_len() and friends, so that should be fixed in 0.24. Unfortunately, to phase those out, we need real symbol versioning support, which llvm appears to have decided not to implement: https://llvm.org/bugs/show_bug.cgi?id=23231 .

So it probably still will not work, because the compiler is flat out broken.

[tpgxyz]

BTW with LLVM/clang-7.0 efivar compiles fine