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/Android.bp b/Android.bp
index 696a963..03bea5a 100644
--- a/Android.bp
+++ b/Android.bp
@@ -62,6 +62,27 @@
     },
 }
 
+soong_config_module_type {
+    name: "avf_flag_aware_cc_defaults",
+    module_type: "cc_defaults",
+    config_namespace: "ANDROID",
+    bool_variables: [
+        "release_avf_enable_virt_cpufreq",
+    ],
+    properties: [
+        "cflags",
+    ],
+}
+
+avf_flag_aware_cc_defaults {
+    name: "avf_build_flags_cc",
+    soong_config_variables: {
+        release_avf_enable_virt_cpufreq: {
+            cflags: ["-DAVF_ENABLE_VIRT_CPUFREQ=1"],
+        },
+    },
+}
+
 genrule_defaults {
     name: "dts_to_dtb",
     tools: ["dtc"],