jni: build android with c++_static

Author: JonasVautherin

jni/CMakeLists.txt

@@ -1,4 +1,8 @@
 cmake_minimum_required(VERSION 3.10.2)
+
+# Must precede project(), which is where the Android toolchain file reads it.
+set(ANDROID_STL "c++_static" CACHE STRING "C++ runtime to link against on Android")
+
 project(mavsdk-jni CXX)
 
 set(CMAKE_CXX_STANDARD 17)
@@ -25,6 +29,10 @@ target_link_libraries(mavsdk_jni CMAVSDK::CMAVSDK)
 
 if(ANDROID)
     target_link_libraries(mavsdk_jni log)
+
+    # Export only the JNIEXPORT entry points, not the static archives or libc++.
+    target_link_options(mavsdk_jni PRIVATE "-Wl,--exclude-libs,ALL")
+    target_compile_options(mavsdk_jni PRIVATE -fvisibility=hidden -fvisibility-inlines-hidden)
 else()
     find_package(JNI REQUIRED)
     target_include_directories(mavsdk_jni PRIVATE ${JNI_INCLUDE_DIRS})