Fix DLL linkage/visibility issues (#2254)

Signed-off-by: Michael Carroll <mjcarroll@intrinsic.ai>

src/CMakeLists.txt

@@ -68,7 +68,6 @@ set (sources
   Util.cc
   View.cc
   World.cc
-  cmd/ModelCommandAPI.cc
   ${PROTO_PRIVATE_SRC}
   ${network_sources}
   ${comms_sources}
@@ -160,7 +159,7 @@ target_link_libraries(${ign_lib_target}
 )
 
 # Executable target that runs the GUI without ruby for debugging purposes.
-add_executable(runGui gz.cc)
+add_executable(runGui cmd/runGui_main.cc)
 target_link_libraries(runGui PRIVATE ${ign_lib_target})
 
 # Create the library target

src/cmd/runGui_main.cc

@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2023 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+*/
+
+#include "gz/sim/gui/Gui.hh"
+
+int main(int argc, char* argv[])
+{
+  return gz::sim::gui::runGui(argc, argv, nullptr);
+}

src/gz.cc

@@ -429,8 +429,3 @@ extern "C" int runGui(const char *_guiConfig, const char *_file, int _waitGui,
   return gz::sim::gui::runGui(
     argc, &argv, _guiConfig, _file, _waitGui, _renderEngine);
 }
-
-int main(int argc, char* argv[])
-{
-  return gazebo::gui::runGui(argc, argv, nullptr);
-}

src/systems/camera_video_recorder/CameraVideoRecorder.cc

@@ -333,7 +333,6 @@ void CameraVideoRecorderPrivate::OnPostRender()
     {
       this->camera->Copy(this->cameraImage);
       std::chrono::steady_clock::time_point t;
-        std::chrono::steady_clock::now();
       if (this->recordVideoUseSimTime)
         t = std::chrono::steady_clock::time_point(this->simTime);
       else