event-lib-plugins: fix symbol export visibility

Co-developed-by: Gemini 2.5 Pro

Author: lws-team

lib/event-libs/CMakeLists.txt

@@ -31,6 +31,10 @@ macro(create_evlib_plugin PLUGIN_NAME MAIN_SRC PLUGIN_HDR EVLIB)
 	source_group("Headers Private"   FILES ${PLUGIN_HDR})
 	source_group("Sources"   FILES ${MAIN_SRC})
 	add_library(websockets-${PLUGIN_NAME} SHARED ${MAIN_SRC} ${PLUGIN_HDR})
+	if (LWS_HAVE_VISIBILITY)
+		set_target_properties(websockets-${PLUGIN_NAME} PROPERTIES
+			C_VISIBILITY_PRESET default)
+	endif()
 
 	if (APPLE)
 		set_property(TARGET websockets-${PLUGIN_NAME} PROPERTY MACOSX_RPATH YES)