syscall: do not use int to test network syscall results (on windows)

Fixes #4147.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6569050

src/pkg/syscall/mksyscall_windows.pl

@@ -266,7 +266,7 @@ while(<>) {
 				$failexpr = "!$name";
 			} elsif($name eq "err") {
 				$ret[$i] = "r1";
-				$failexpr = "int(r1) $failcond";
+				$failexpr = "r1 $failcond";
 			} else {
 				$failexpr = "$name $failcond";
 			}

src/pkg/syscall/syscall_windows.go

@@ -468,25 +468,27 @@ func Chmod(path string, mode uint32) (err error) {
 
 // net api calls
 
+const socket_error = uintptr(^uint32(0))
+
 //sys	WSAStartup(verreq uint32, data *WSAData) (sockerr error) = ws2_32.WSAStartup
-//sys	WSACleanup() (err error) [failretval==-1] = ws2_32.WSACleanup
-//sys	WSAIoctl(s Handle, iocc uint32, inbuf *byte, cbif uint32, outbuf *byte, cbob uint32, cbbr *uint32, overlapped *Overlapped, completionRoutine uintptr) (err error) [failretval==-1] = ws2_32.WSAIoctl
+//sys	WSACleanup() (err error) [failretval==socket_error] = ws2_32.WSACleanup
+//sys	WSAIoctl(s Handle, iocc uint32, inbuf *byte, cbif uint32, outbuf *byte, cbob uint32, cbbr *uint32, overlapped *Overlapped, completionRoutine uintptr) (err error) [failretval==socket_error] = ws2_32.WSAIoctl
 //sys	socket(af int32, typ int32, protocol int32) (handle Handle, err error) [failretval==InvalidHandle] = ws2_32.socket
-//sys	Setsockopt(s Handle, level int32, optname int32, optval *byte, optlen int32) (err error) [failretval==-1] = ws2_32.setsockopt
-//sys	Getsockopt(s Handle, level int32, optname int32, optval *byte, optlen *int32) (err error) [failretval==-1] = ws2_32.getsockopt
-//sys	bind(s Handle, name uintptr, namelen int32) (err error) [failretval==-1] = ws2_32.bind
-//sys	connect(s Handle, name uintptr, namelen int32) (err error) [failretval==-1] = ws2_32.connect
-//sys	getsockname(s Handle, rsa *RawSockaddrAny, addrlen *int32) (err error) [failretval==-1] = ws2_32.getsockname
-//sys	getpeername(s Handle, rsa *RawSockaddrAny, addrlen *int32) (err error) [failretval==-1] = ws2_32.getpeername
-//sys	listen(s Handle, backlog int32) (err error) [failretval==-1] = ws2_32.listen
-//sys	shutdown(s Handle, how int32) (err error) [failretval==-1] = ws2_32.shutdown
-//sys	Closesocket(s Handle) (err error) [failretval==-1] = ws2_32.closesocket
+//sys	Setsockopt(s Handle, level int32, optname int32, optval *byte, optlen int32) (err error) [failretval==socket_error] = ws2_32.setsockopt
+//sys	Getsockopt(s Handle, level int32, optname int32, optval *byte, optlen *int32) (err error) [failretval==socket_error] = ws2_32.getsockopt
+//sys	bind(s Handle, name uintptr, namelen int32) (err error) [failretval==socket_error] = ws2_32.bind
+//sys	connect(s Handle, name uintptr, namelen int32) (err error) [failretval==socket_error] = ws2_32.connect
+//sys	getsockname(s Handle, rsa *RawSockaddrAny, addrlen *int32) (err error) [failretval==socket_error] = ws2_32.getsockname
+//sys	getpeername(s Handle, rsa *RawSockaddrAny, addrlen *int32) (err error) [failretval==socket_error] = ws2_32.getpeername
+//sys	listen(s Handle, backlog int32) (err error) [failretval==socket_error] = ws2_32.listen
+//sys	shutdown(s Handle, how int32) (err error) [failretval==socket_error] = ws2_32.shutdown
+//sys	Closesocket(s Handle) (err error) [failretval==socket_error] = ws2_32.closesocket
 //sys	AcceptEx(ls Handle, as Handle, buf *byte, rxdatalen uint32, laddrlen uint32, raddrlen uint32, recvd *uint32, overlapped *Overlapped) (err error) = mswsock.AcceptEx
 //sys	GetAcceptExSockaddrs(buf *byte, rxdatalen uint32, laddrlen uint32, raddrlen uint32, lrsa **RawSockaddrAny, lrsalen *int32, rrsa **RawSockaddrAny, rrsalen *int32) = mswsock.GetAcceptExSockaddrs
-//sys	WSARecv(s Handle, bufs *WSABuf, bufcnt uint32, recvd *uint32, flags *uint32, overlapped *Overlapped, croutine *byte) (err error) [failretval==-1] = ws2_32.WSARecv
-//sys	WSASend(s Handle, bufs *WSABuf, bufcnt uint32, sent *uint32, flags uint32, overlapped *Overlapped, croutine *byte) (err error) [failretval==-1] = ws2_32.WSASend
-//sys	WSARecvFrom(s Handle, bufs *WSABuf, bufcnt uint32, recvd *uint32, flags *uint32,  from *RawSockaddrAny, fromlen *int32, overlapped *Overlapped, croutine *byte) (err error) [failretval==-1] = ws2_32.WSARecvFrom
-//sys	WSASendTo(s Handle, bufs *WSABuf, bufcnt uint32, sent *uint32, flags uint32, to *RawSockaddrAny, tolen int32,  overlapped *Overlapped, croutine *byte) (err error) [failretval==-1] = ws2_32.WSASendTo
+//sys	WSARecv(s Handle, bufs *WSABuf, bufcnt uint32, recvd *uint32, flags *uint32, overlapped *Overlapped, croutine *byte) (err error) [failretval==socket_error] = ws2_32.WSARecv
+//sys	WSASend(s Handle, bufs *WSABuf, bufcnt uint32, sent *uint32, flags uint32, overlapped *Overlapped, croutine *byte) (err error) [failretval==socket_error] = ws2_32.WSASend
+//sys	WSARecvFrom(s Handle, bufs *WSABuf, bufcnt uint32, recvd *uint32, flags *uint32,  from *RawSockaddrAny, fromlen *int32, overlapped *Overlapped, croutine *byte) (err error) [failretval==socket_error] = ws2_32.WSARecvFrom
+//sys	WSASendTo(s Handle, bufs *WSABuf, bufcnt uint32, sent *uint32, flags uint32, to *RawSockaddrAny, tolen int32,  overlapped *Overlapped, croutine *byte) (err error) [failretval==socket_error] = ws2_32.WSASendTo
 //sys	GetHostByName(name string) (h *Hostent, err error) [failretval==nil] = ws2_32.gethostbyname
 //sys	GetServByName(name string, proto string) (s *Servent, err error) [failretval==nil] = ws2_32.getservbyname
 //sys	Ntohs(netshort uint16) (u uint16) = ws2_32.ntohs