Use visibility hidden by default

Signed-off-by: Jose Luis Rivero <[email protected]>

cmake/GzConfigureBuild.cmake

@@ -24,16 +24,22 @@
 #################################################
 # Configure the build of the Gazebo project
 # Pass the argument HIDE_SYMBOLS_BY_DEFAULT to configure symbol visibility so
-# that symbols are hidden unless explicitly marked as visible.
+# that symbols are hidden unless explicitly marked as visible. (DEPRECATED)
+# Pass the argument EXPOSE_SYMBOLS_BY_DEFAULT to configure symbol visibility
+# so symbols are exposed unless explicitly marked as hidden.
 # Pass the argument QUIT_IF_BUILD_ERRORS to have this macro quit cmake when the
 # build_errors
 macro(gz_configure_build)
   # Parse the arguments that are passed in
-  set(options HIDE_SYMBOLS_BY_DEFAULT QUIT_IF_BUILD_ERRORS)
+  set(options HIDE_SYMBOLS_BY_DEFAULT EXPOSE_SYMBOLS_BY_DEFAULT QUIT_IF_BUILD_ERRORS)
   set(oneValueArgs)
   set(multiValueArgs COMPONENTS)
   cmake_parse_arguments(gz_configure_build "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
 
+  if(gz_configure_build_HIDE_SYMBOLS_BY_DEFAULT)
+    message(DEPRECATION "HIDE_SYMBOLS_BY_DEFAULT is now the default. You can safely remove the option.")
+  endif()
+
   #============================================================================
   # Examine the build type. If we do not recognize the type, we will generate
   # an error, so this must come before the error handling.

cmake/GzSetCompilerFlags.cmake

@@ -123,12 +123,12 @@ endmacro()
 # Internal to gz-cmake.
 macro(_gz_setup_gcc_or_clang)
 
-  if(gz_configure_build_HIDE_SYMBOLS_BY_DEFAULT)
-    set(CMAKE_C_VISIBILITY_PRESET "hidden")
-    set(CMAKE_CXX_VISIBILITY_PRESET "hidden")
-  else()
+  if(gz_configure_build_EXPOSE_SYMBOLS_BY_DEFAULT)
     set(CMAKE_C_VISIBILITY_PRESET "default")
     set(CMAKE_CXX_VISIBILITY_PRESET "default")
+  else()
+    set(CMAKE_C_VISIBILITY_PRESET "hidden")
+    set(CMAKE_CXX_VISIBILITY_PRESET "hidden")
   endif()