syscall: update BSD variants to sync with new os/signal

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/5661051

src/pkg/syscall/syscall_freebsd.go

@@ -146,7 +146,7 @@ func SetsockoptIPMreqn(fd, level, opt int, mreq *IPMreqn) (err error) {
 //sysnb	Gettimeofday(tv *Timeval) (err error)
 //sysnb	Getuid() (uid int)
 //sys	Issetugid() (tainted bool)
-//sys	Kill(pid int, signum int) (err error)
+//sys	Kill(pid int, signum Signal) (err error)
 //sys	Kqueue() (fd int, err error)
 //sys	Lchown(path string, uid int, gid int) (err error)
 //sys	Link(path string, link string) (err error)

src/pkg/syscall/syscall_netbsd.go

@@ -119,7 +119,7 @@ func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 //sysnb	Gettimeofday(tv *Timeval) (err error)
 //sysnb	Getuid() (uid int)
 //sys	Issetugid() (tainted bool)
-//sys	Kill(pid int, signum int) (err error)
+//sys	Kill(pid int, signum Signal) (err error)
 //sys	Kqueue() (fd int, err error)
 //sys	Lchown(path string, uid int, gid int) (err error)
 //sys	Link(path string, link string) (err error)

src/pkg/syscall/syscall_openbsd.go

@@ -135,7 +135,7 @@ func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 //sysnb	Gettimeofday(tv *Timeval) (err error)
 //sysnb	Getuid() (uid int)
 //sys	Issetugid() (tainted bool)
-//sys	Kill(pid int, signum int) (err error)
+//sys	Kill(pid int, signum Signal) (err error)
 //sys	Kqueue() (fd int, err error)
 //sys	Lchown(path string, uid int, gid int) (err error)
 //sys	Link(path string, link string) (err error)