diff -up ./CMakeLists.txt.automoc ./CMakeLists.txt

--- ./CMakeLists.txt.automoc	2019-03-28 20:58:30.000000000 -0400

+++ ./CMakeLists.txt	2020-08-22 18:22:13.315277325 -0400

@@ -3,6 +3,7 @@ cmake_minimum_required(VERSION 2.8.6 FAT

 if(COMMAND CMAKE_POLICY)

   CMAKE_POLICY(SET CMP0003 NEW)

   CMAKE_POLICY(SET CMP0004 NEW)

+  CMAKE_POLICY(SET CMP0100 NEW)

 endif(COMMAND CMAKE_POLICY)

 project (Gazebo)

@@ -250,7 +251,7 @@ filter_valid_compiler_flags(${WARN_LEVEL

 # Check and add visibility hidden by default. Only in UNIX

 # Windows and MacosX does not handled properly the hidden compilation

 if (UNIX AND NOT APPLE)

-  filter_valid_compiler_flags(-fvisibility=hidden -fvisibility-inlines-hidden)

+  filter_valid_compiler_flags(-fvisibility-inlines-hidden)

 endif()

 if (MSVC)

@@ -260,9 +261,8 @@ if (MSVC)

 endif()

 # Visual Studio enables c++11 support by default

-if (NOT MSVC)

-  set(UNFILTERED_FLAGS "-std=c++11")

-endif()

+set(CMAKE_CXX_STANDARD 11)

+set(CMAKE_CXX_EXTENSIONS OFF)

 set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${VALID_CXX_FLAGS} ${UNFILTERED_FLAGS}")