Correct the regexp for finding unix signal names.

  For example, earlier, the regexp would accept SIGQUEUE_MAX
  as a unix signal with name SIGQUEUE. Now it is ignored.

R=iant
CC=golang-dev, golang-nuts, joel.sherrill
https://golang.org/cl/1452041

src/pkg/os/signal/mkunix.sh

@@ -19,6 +19,6 @@ var _ = syscall.Syscall  // in case there are zero signals
 const (
 EOH
 
-sed -n 's/^[ 	]*\(SIG[A-Z0-9][A-Z0-9]*\).*/  \1 = UnixSignal(syscall.\1)/p' "$1"
+sed -n 's/^[ 	]*\(SIG[A-Z0-9][A-Z0-9]*\)[ 	].*/  \1 = UnixSignal(syscall.\1)/p' "$1"
 
 echo ")"