soong: Add flag for fod extension

Change-Id: Ib45706cc50fa88b9b05af1c68eec9d1f08d70569
diff --git a/build/soong/android/variable.go b/build/soong/android/variable.go
index 0822528..da8ed0e 100644
--- a/build/soong/android/variable.go
+++ b/build/soong/android/variable.go
@@ -25,6 +25,10 @@
     Target_enforce_ab_ota_partition_list struct {
         Cflags []string
     }
+    Target_surfaceflinger_fod_lib struct {
+        Cflags []string
+        Whole_static_libs []string
+    }
 }
 
 type ProductVariables struct {
@@ -37,4 +41,5 @@
     Target_motorized_camera                 *bool `json:",omitempty"`
     Target_init_vendor_lib                  *string `json:",omitempty"`
     Target_enforce_ab_ota_partition_list    *bool `json:",omitempty"`
+	Target_surfaceflinger_fod_lib            *string `json:",omitempty"`
 }