Add support for defaults modules

Add a cc_defaults module, which will prepend any matching properties to
modules that reference it with a "defaults" property.

Change-Id: I5908dd98d204f71b29ad95a4ab85403aa1621ca2
diff --git a/common/module.go b/common/module.go
index 1860ecb..69da7c6 100644
--- a/common/module.go
+++ b/common/module.go
@@ -127,6 +127,7 @@
 
 	base := m.base()
 	base.commonProperties.HostOrDeviceSupported = hod
+	base.commonProperties.Compile_multilib = string(defaultMultilib)
 
 	if hod == HostAndDeviceSupported {
 		// Default to module to device supported, host not supported, can override in module
@@ -135,7 +136,7 @@
 		propertyStructs = append(propertyStructs, &base.hostAndDeviceProperties)
 	}
 
-	return InitArchModule(m, defaultMultilib, propertyStructs...)
+	return InitArchModule(m, propertyStructs...)
 }
 
 // A AndroidModuleBase object contains the properties that are common to all Android