Make libstagefright_aacenc depend on libbinder

This library includes libstagefright headers, which in turn
include libbinder headers.  Unfortunately, introducing a
dependency on libstagefright directly introduces a circular dependency.

Bug: 27804373
Change-Id: Id1e65f99b63275ffdccb05638412f43825f8ec1c
Test: Compiles with accompanying changes.
diff --git a/media/libstagefright/codecs/aacenc/Android.mk b/media/libstagefright/codecs/aacenc/Android.mk
index 266f01b..71c374b 100644
--- a/media/libstagefright/codecs/aacenc/Android.mk
+++ b/media/libstagefright/codecs/aacenc/Android.mk
@@ -64,7 +64,10 @@
 
 LOCAL_STATIC_LIBRARIES :=
 
-LOCAL_SHARED_LIBRARIES :=
+# libstagefright links this static library, so it probably isn't appropriate to
+# link libstagefright.  However, this library includes libstagefright headers,
+# and needs libbinder to be able to do so correctly.
+LOCAL_SHARED_LIBRARIES := libbinder
 
 LOCAL_C_INCLUDES := \
 	frameworks/av/include \