Add support for cc_library_headers to replace llndk_headers

Set llndk.llndk_headers: true to allow a cc_library_headers
module to be used by a cc_library module with llndk.symbol_file set.

Bug: 170784825
Test: TestLlndkHeaders
Change-Id: Ib65a4b70717dc9a54ae30f2991485bb1bb9b8409
diff --git a/rust/rust.go b/rust/rust.go
index 78a793d..e1a69c0 100644
--- a/rust/rust.go
+++ b/rust/rust.go
@@ -274,7 +274,7 @@
 	return false
 }
 
-func (m *Module) HasLlndkStubs() bool {
+func (m *Module) NeedsLlndkVariants() bool {
 	return false
 }