Export build flags to soong.

This exports a map of build flags used in this release config to Soong.

Bug: 302514918
Test: manual
Change-Id: Id95c03e14cfbb91c0cb9c8c37a065b8387733317
diff --git a/android/config.go b/android/config.go
index 213fa2f..4c31bb0 100644
--- a/android/config.go
+++ b/android/config.go
@@ -2124,3 +2124,8 @@
 func (c *deviceConfig) HideFlaggedApis() bool {
 	return c.NextReleaseHideFlaggedApi() && !c.ReleaseExposeFlaggedApi()
 }
+
+func (c *config) GetBuildFlag(name string) (string, bool) {
+	val, ok := c.productVariables.BuildFlags[name]
+	return val, ok
+}