libbinder_ndk: binder_stability.h markVintf weak

This was causing loading errors for Q targets which include this.
Separately, we want to use __INTRODUCED_IN here, but it causes
false positive hits for that static inline void functions which
are declared here.

Bug: 227835797
Test: N/A
Change-Id: I225418b53c7fd83c291ece15cc8f9df3ed37eaad
diff --git a/libs/binder/ndk/include_platform/android/binder_stability.h b/libs/binder/ndk/include_platform/android/binder_stability.h
index f113ba8..d0cd11f 100644
--- a/libs/binder/ndk/include_platform/android/binder_stability.h
+++ b/libs/binder/ndk/include_platform/android/binder_stability.h
@@ -97,6 +97,10 @@
  *
  * This interface has system<->vendor stability
  */
+// b/227835797 - can't use __INTRODUCED_IN(30) because old targets load this code
+#if __ANDROID_MIN_SDK_VERSION__ < 30
+__attribute__((weak))
+#endif  // __ANDROID_MIN_SDK_VERSION__ < 30
 void AIBinder_markVintfStability(AIBinder* binder);
 
 __END_DECLS