syscall: fix build. WUNTRACED isn't defined for win32.

For Windows, the options for syscall.Wait4() aren't used.
Then this will be dummy value like WNOHANG, WSTOPPED.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4075041

diff --git a/src/pkg/syscall/syscall_windows.go b/src/pkg/syscall/syscall_windows.go
index 33a86ce251eb3081a81ba8407cb310607178caf4..06dde518fdc5e6f9e91cb868967a64f976ac43ec 100644 (file)
--- a/src/pkg/syscall/syscall_windows.go
+++ b/src/pkg/syscall/syscall_windows.go
@@ -708,6 +708,7 @@ const (
        PTRACE_TRACEME = 1 + iota
        WNOHANG
        WSTOPPED
+       WUNTRACED
        SYS_CLOSE
        SYS_WRITE
        SYS_EXIT