clang/llvm failure on a project branch

[Sean Bruno]

Not sure if I really need to have this code yet, but I found a bit of
code that works under gcc but fails under clang/llvm on my project
branch of pxe_http:

http://svnweb.freebsd.org/base/user/sbruno/pxe_http_head/sys/boot/i386/pxe_http/

===> i386/pxe_http (all)
pxe_isr.S:45:3: error: unexpected directive .code16
  .code16
  ^
pxe_isr.S:45:10: error: .code16 not supported yet
  .code16
         ^
*** [pxe_isr.o] Error code 1

Stop in /home/sbruno/sbruno/pxe_http_head/sys/boot/i386/pxe_http.
*** [all] Error code 1

Stop in /home/sbruno/sbruno/pxe_http_head/sys/boot/i386.
*** [all] Error code 1

Stop in /home/sbruno/sbruno/pxe_http_head/sys/boot.