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/authfs/tests/benchmarks/Android.bp b/authfs/tests/benchmarks/Android.bp
index 5ef01cc..5820cb4 100644
--- a/authfs/tests/benchmarks/Android.bp
+++ b/authfs/tests/benchmarks/Android.bp
@@ -29,6 +29,7 @@
 
 cc_binary {
     name: "measure_io",
+    defaults: ["avf_build_flags_cc"],
     srcs: [
         "src/measure_io.cpp",
     ],