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/compos/compos_key_helper/Android.bp b/compos/compos_key_helper/Android.bp
index 6b4b61e..7d27525 100644
--- a/compos/compos_key_helper/Android.bp
+++ b/compos/compos_key_helper/Android.bp
@@ -5,6 +5,7 @@
 
 cc_defaults {
     name: "compos_key_defaults",
+    defaults: ["avf_build_flags_cc"],
     apex_available: ["com.android.compos"],
 
     shared_libs: [