Introduce avf_build_flags_cc cc_defaults

These are similar to avf_build_rust_build flags, but for cc_* soong
modules.

In the immediate future this will be used for flag guarding
virtcpu-freq related changes to platform.dts.

This patch also adds avf_build_flags_cc as cc_defaults to all our
existing cc_* soong modules

Test: builds
Bug: 284369518
Change-Id: I19152675802548cd9efba30a40bccdbb14867fe1
diff --git a/apex/empty-payload-apk/Android.bp b/apex/empty-payload-apk/Android.bp
index e78daec..72ec392 100644
--- a/apex/empty-payload-apk/Android.bp
+++ b/apex/empty-payload-apk/Android.bp
@@ -18,6 +18,7 @@
 
 cc_library {
     name: "MicrodroidEmptyPayloadJniLib",
+    defaults: ["avf_build_flags_cc"],
     srcs: ["empty_binary.cpp"],
     shared_libs: ["libvm_payload#current"],
     installable: true,