rust: add aconfig_flag support

Bug: b/308625757
Test: manual
Change-Id: Ifd98cd0ad4e2525b08f5766e9332991c049162ea
diff --git a/rust/androidmk.go b/rust/androidmk.go
index e02c3f6..733ffc5 100644
--- a/rust/androidmk.go
+++ b/rust/androidmk.go
@@ -66,7 +66,8 @@
 				if mod.UseVndk() {
 					entries.SetBool("LOCAL_USE_VNDK", true)
 				}
-
+				// TODO(b/311155208): The container here should be system.
+				entries.SetPaths("LOCAL_ACONFIG_FILES", mod.mergedAconfigFiles[""])
 			},
 		},
 	}