Android: Link to android_support with c++_shared

The NDK has done this in `build/core/definitions.mk` since r13
(r12 and below do so only for c++_static).

Modules/Platform/Android/ndk-stl-c++_shared.cmake

@@ -1,4 +1,5 @@
 include(Platform/Android/ndk-stl-c++)
 macro(__android_stl lang)
   __android_stl_cxx(${lang} libc++_shared.so)
+  __android_stl_lib(${lang} "${CMAKE_ANDROID_NDK}/sources/cxx-stl/llvm-libc++/libs/${CMAKE_ANDROID_ARCH_ABI}/libandroid_support.a" 0)
 endmacro()