head is broken after recent sys_pipe changes

As of this commit:

r302106 | adrian | 2016-06-22 21:15:35 -0400 (Wed, 22 Jun 2016) | 4 lines

revert error commit from previous commit. my bad!

Approved by:    re (implicit)

Head still doesn't compile doing:

make -k -s -j24 tinderbox TARGETS="amd64 sparc64"

Tinderbox failed:
amd64.amd64 buildworld failed, check _.amd64.amd64.buildworld for details

===> lib/csu/amd64 (obj)
===> lib/csu/amd64 (all)
===> lib/csu/amd64 (install)
bmake[6]: /usr/obj/p/fbsd/GIT/lib/libc/.depend.pipe.o, 5: ignoring stale 
.depend
  for /p/fbsd/GIT/lib/libc/amd64/sys/pipe.S
cc: error: no such file or directory: 
'/p/fbsd/GIT/lib/libc/amd64/sys/pipe.S'
cc: error: no input files
--- pipe.So ---
*** [pipe.So] Error code 1

bmake[6]: stopped in /p/fbsd/GIT/lib/libc
cc: error: no such file or directory: 
'/p/fbsd/GIT/lib/libc/amd64/sys/pipe.S'
cc: error: no input files
--- pipe.o ---
*** [pipe.o] Error code 1

-Kurt