Integrate android support library into our cmake build

Just meant for integration testing. Built library is not meant to
be installed or shipped. This has to happen as part of the Android
build.

android/CMakeLists.txt

@@ -0,0 +1,10 @@
+set(ANBOX_SUPPORT_SOURCES
+    jni/anbox_support.cpp)
+
+include_directories(
+    ${CMAKE_SOURCE_DIR}/external/jni)
+
+# We're not going to ship this, just building here to add proper
+# unit tests we can run in a integration system without having
+# the Android build system around.
+add_library(anbox-support ${ANBOX_SUPPORT_SOURCES})

android/jni/anbox_support.cpp

@@ -20,7 +20,11 @@
 
 #define LOG_TAG "AnboxSupport"
 
+#ifdef ANDROID
 #include <utils/Log.h>
+#else
+#define ALOGI(...)
+#endif
 
 extern "C" jint JNI_OnLoad(JavaVM* vm, void* reserved) {
     ALOGI("Successfully loaded Anbox support library");