api: add openbsd syscall constants

Change-Id: I3ec00dac5e7d0e6dcafb7d65851bc53e0661c2b6
Reviewed-on: https://go-review.googlesource.com/34500Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

api/go1.8.txt

@@ -246,6 +246,10 @@ pkg sort, func SliceIsSorted(interface{}, func(int, int) bool) bool
 pkg sort, func SliceStable(interface{}, func(int, int) bool)
 pkg syscall (linux-arm-cgo), func TimevalToNsec(Timeval) int64
 pkg syscall (linux-arm), func TimevalToNsec(Timeval) int64
+pkg syscall (openbsd-386), const SYS_KILL = 122
+pkg syscall (openbsd-386-cgo), const SYS_KILL = 122
+pkg syscall (openbsd-amd64), const SYS_KILL = 122
+pkg syscall (openbsd-amd64-cgo), const SYS_KILL = 122
 pkg syscall (windows-386), const ERROR_DIR_NOT_EMPTY = 145
 pkg syscall (windows-386), const ERROR_DIR_NOT_EMPTY Errno
 pkg syscall (windows-amd64), const ERROR_DIR_NOT_EMPTY = 145