Unit testing for def/ module.

Added unit tests to test code in def/ module.

vendor/golang.org/x/sys/unix/sockcmsg_unix.go

@@ -8,17 +8,33 @@
 
 package unix
 
-import "unsafe"
+import (
+	"runtime"
+	"unsafe"
+)
 
 // Round the length of a raw sockaddr up to align it properly.
 func cmsgAlignOf(salen int) int {
-	salign := sizeofPtr
-	// NOTE: It seems like 64-bit Darwin, DragonFly BSD and
-	// Solaris kernels still require 32-bit aligned access to
-	// network subsystem.
-	if darwin64Bit || dragonfly64Bit || solaris64Bit {
-		salign = 4
+	salign := SizeofPtr
+
+	switch runtime.GOOS {
+	case "aix":
+		// There is no alignment on AIX.
+		salign = 1
+	case "darwin", "dragonfly", "solaris", "illumos":
+		// NOTE: It seems like 64-bit Darwin, DragonFly BSD,
+		// illumos, and Solaris kernels still require 32-bit
+		// aligned access to network subsystem.
+		if SizeofPtr == 8 {
+			salign = 4
+		}
+	case "netbsd", "openbsd":
+		// NetBSD and OpenBSD armv7 require 64-bit alignment.
+		if runtime.GOARCH == "arm" {
+			salign = 8
+		}
 	}
+
 	return (salen + salign - 1) & ^(salign - 1)
 }