net: use windows sysSocket everywhere

R=golang-dev, bradfitz, dave
CC=golang-dev
https://golang.org/cl/7273046

src/pkg/net/fd_windows.go

@@ -619,15 +619,10 @@ func (fd *netFD) accept(toAddr func(syscall.Sockaddr) Addr) (*netFD, error) {
 	defer fd.decref()
 
 	// Get new socket.
-	// See ../syscall/exec_unix.go for description of ForkLock.
-	syscall.ForkLock.RLock()
-	s, err := syscall.Socket(fd.family, fd.sotype, 0)
+	s, err := sysSocket(fd.family, fd.sotype, 0)
 	if err != nil {
-		syscall.ForkLock.RUnlock()
 		return nil, &OpError{"socket", fd.net, fd.laddr, err}
 	}
-	syscall.CloseOnExec(s)
-	syscall.ForkLock.RUnlock()
 
 	// Associate our new socket with IOCP.
 	onceStartServer.Do(startServer)

src/pkg/net/interface_windows.go

@@ -38,7 +38,7 @@ func getAdapterList() (*syscall.IpAdapterInfo, error) {
 }
 
 func getInterfaceList() ([]syscall.InterfaceInfo, error) {
-	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_UDP)
+	s, err := sysSocket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_UDP)
 	if err != nil {
 		return nil, os.NewSyscallError("Socket", err)
 	}