Merge pull request #42413 from thaJeztah/20.10_backport_bump_libnetwork

[20.10 backport] vendor: github.com/docker/libnetwork 64b7a4574d1426139437d20e81c0b6d391130ec8 
diff --git a/pkg/signal/signal.go b/pkg/signal/signal.go
index bbe006b..b274033 100644
--- a/pkg/signal/signal.go
+++ b/pkg/signal/signal.go
@@ -12,13 +12,13 @@
 )
 
 // CatchAll catches all signals and relays them to the specified channel.
-// On Linux, SIGURG is not handled, as it's used by the Go runtime to support
+// SIGURG is not handled, as it's used by the Go runtime to support
 // preemptable system calls.
 func CatchAll(sigc chan os.Signal) {
 	var handledSigs []os.Signal
-	for _, s := range SignalMap {
-		if isRuntimeSig(s) {
-			// Do not handle SIGURG on Linux, as in go1.14+, the go runtime issues
+	for n, s := range SignalMap {
+		if n == "URG" {
+			// Do not handle SIGURG, as in go1.14+, the go runtime issues
 			// SIGURG as an interrupt to support preemptable system calls on Linux.
 			continue
 		}
diff --git a/pkg/signal/signal_darwin.go b/pkg/signal/signal_darwin.go
index 8ffd3d7..ee5501e 100644
--- a/pkg/signal/signal_darwin.go
+++ b/pkg/signal/signal_darwin.go
@@ -1,7 +1,6 @@
 package signal // import "github.com/docker/docker/pkg/signal"
 
 import (
-	"os"
 	"syscall"
 )
 
@@ -40,7 +39,3 @@
 	"XCPU":   syscall.SIGXCPU,
 	"XFSZ":   syscall.SIGXFSZ,
 }
-
-func isRuntimeSig(_ os.Signal) bool {
-	return false
-}
diff --git a/pkg/signal/signal_freebsd.go b/pkg/signal/signal_freebsd.go
index a5e774a..764f90e 100644
--- a/pkg/signal/signal_freebsd.go
+++ b/pkg/signal/signal_freebsd.go
@@ -1,7 +1,6 @@
 package signal // import "github.com/docker/docker/pkg/signal"
 
 import (
-	"os"
 	"syscall"
 )
 
@@ -42,7 +41,3 @@
 	"XCPU":   syscall.SIGXCPU,
 	"XFSZ":   syscall.SIGXFSZ,
 }
-
-func isRuntimeSig(_ os.Signal) bool {
-	return false
-}
diff --git a/pkg/signal/signal_linux.go b/pkg/signal/signal_linux.go
index 46fe6bb..4013bde 100644
--- a/pkg/signal/signal_linux.go
+++ b/pkg/signal/signal_linux.go
@@ -3,7 +3,6 @@
 package signal // import "github.com/docker/docker/pkg/signal"
 
 import (
-	"os"
 	"syscall"
 
 	"golang.org/x/sys/unix"
@@ -82,7 +81,3 @@
 	"RTMAX-1":  sigrtmax - 1,
 	"RTMAX":    sigrtmax,
 }
-
-func isRuntimeSig(s os.Signal) bool {
-	return s == unix.SIGURG
-}
diff --git a/pkg/signal/signal_linux_mipsx.go b/pkg/signal/signal_linux_mipsx.go
index 665d849..c78c887 100644
--- a/pkg/signal/signal_linux_mipsx.go
+++ b/pkg/signal/signal_linux_mipsx.go
@@ -4,7 +4,6 @@
 package signal // import "github.com/docker/docker/pkg/signal"
 
 import (
-	"os"
 	"syscall"
 
 	"golang.org/x/sys/unix"
@@ -83,7 +82,3 @@
 	"RTMAX-1":  sigrtmax - 1,
 	"RTMAX":    sigrtmax,
 }
-
-func isRuntimeSig(s os.Signal) bool {
-	return s == unix.SIGURG
-}
diff --git a/pkg/signal/signal_windows.go b/pkg/signal/signal_windows.go
index d44662c..65752f2 100644
--- a/pkg/signal/signal_windows.go
+++ b/pkg/signal/signal_windows.go
@@ -1,7 +1,6 @@
 package signal // import "github.com/docker/docker/pkg/signal"
 
 import (
-	"os"
 	"syscall"
 )
 
@@ -25,7 +24,3 @@
 	"KILL": syscall.SIGKILL,
 	"TERM": syscall.SIGTERM,
 }
-
-func isRuntimeSig(_ os.Signal) bool {
-	return false
-}