Merge remote-tracking branch 'origin/shebs/clangify' into local-v5

* origin/shebs/clangify:
  Use clang integrated assembler except when asm is output and not required to be valid
  Add workaround to get clang to accept avx-512 instructions
  Work around clang assembler error with bnd by itself on a line
  Work around clang assembler error with movzx
  Work around clang assembler bug with expressions in .if
  Work around lack of .tfloat in clang assembler