Break a dependency of libui on libandroid

This was only a header dependency, but it still
created a circular dependency, which will cause
problems in another CL.

We fix this by creating a libarect static library
containing only that header. both libui and
libandroid now depend on it and reexport the 
header. 

We also make sure rect.h ends-up in the right
place.

Test: built and booted device
Bug: 35164655

Change-Id: Iba25b8b801b26b26ec1401c00caf367a06f197ca
diff --git a/opengl/tests/hwc/Android.mk b/opengl/tests/hwc/Android.mk
index 693fba4..13337c2 100644
--- a/opengl/tests/hwc/Android.mk
+++ b/opengl/tests/hwc/Android.mk
@@ -25,6 +25,8 @@
 LOCAL_C_INCLUDES += system/extras/tests/include \
     $(call include-path-for, opengl-tests-includes) \
 
+LOCAL_STATIC_LIBRARIES := libarect
+
 include $(BUILD_STATIC_LIBRARY)
 
 include $(CLEAR_VARS)