cc_cmake_snapshot: improve support for AIDL

- link correct libbinder for AIDL modules
- fix building AIDL interfaces with non-empty AidlRoot
- don't silently drop non-existent dependencies

Bug: 302718225
Test: aosp/3081709
      atest binder_sdk_docker_test_clang
Change-Id: I181ef5a994f728f8af19134a6697b065a9aee261
diff --git a/cc/compiler.go b/cc/compiler.go
index aee584d..9187b9b 100644
--- a/cc/compiler.go
+++ b/cc/compiler.go
@@ -147,6 +147,9 @@
 		// list of aidl_interface sources
 		Sources []string `blueprint:"mutated"`
 
+		// root directory of AIDL sources
+		AidlRoot string `blueprint:"mutated"`
+
 		// AIDL backend language (e.g. "cpp", "ndk")
 		Lang string `blueprint:"mutated"`