Merge pull request godotengine#1563 from APokorny/visibility-hidden

Add visibility-hidden to CMake build

Author: dsnopek

CMakeLists.txt

@@ -35,6 +35,10 @@
 # Generate the buildfiles in a sub directory to not clutter the root directory with build files:
 # mkdir build && cd build && cmake -G "Unix Makefiles" .. && cmake --build .
 #
+# Ensure that you avoid exposing godot-cpp symbols - this might lead to hard to debug errors if you ever load multiple
+# plugins using difference godot-cpp versions. Use visibility hidden whenever possible:
+# set_target_properties(<all-my-plugin-related-targets> PROPERTIES CXX_VISIBILITY_PRESET hidden)
+#
 # Todo
 # Test build for Windows, Mac and mingw.
 
@@ -222,6 +226,7 @@ set_target_properties(${PROJECT_NAME}
 PROPERTIES
 CXX_EXTENSIONS OFF
 POSITION_INDEPENDENT_CODE ON
+CXX_VISIBILITY_PRESET hidden
 ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/bin"
 LIBRARY_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/bin"
 RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/bin"