Fix RS build.

ANativeWindowBuffer is not available in the NDK, so make it opaque.
This also fixes a broken merge of mine.

Change-Id: I6f07776ec2b6b147edd9e70646d71581d01a93a6
diff --git a/rsContext.cpp b/rsContext.cpp
index cabc1bb..0457595 100644
--- a/rsContext.cpp
+++ b/rsContext.cpp
@@ -34,7 +34,8 @@
 #include <dlfcn.h>
 #include <unistd.h>
 
-#if !defined(RS_SERVER) && !defined(RS_COMPATIBILITY_LIB)
+#if !defined(RS_SERVER) && !defined(RS_COMPATIBILITY_LIB) && \
+        defined(HAVE_ANDROID_OS)
 #include <cutils/properties.h>
 #endif