Add product_sdk_version.cflags property

libwilhelm needs PRODUCT_SDK_VERSION=%d.

Test: builds
Change-Id: Ie3caf9e4fdcb8e241c8743b1675520e93cf20cae

android/variable.go

@@ -33,6 +33,7 @@ type variableProperties struct {
 	Product_variables struct {
 		Platform_sdk_version struct {
 			Asflags []string
+			Cflags  []string
 		}
 
 		// unbundled_build is a catch-all property to annotate modules that don't build in one or