Set compile symbol visibility to hidden in cmake (#3655)

Set compile symbol visibility to hidden in cmake of root folder and
product-mini/platforms/linux.

CMakeLists.txt

@@ -121,7 +121,7 @@ set (WAMR_ROOT_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 
 include (${WAMR_ROOT_DIR}/build-scripts/runtime_lib.cmake)
 
-set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wformat -Wformat-security -Wshadow -Wno-unused-parameter")
+set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wformat -Wformat-security -Wshadow -Wno-unused-parameter -fvisibility=hidden")
 # set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wconversion -Wsign-conversion")
 
 set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wformat -Wformat-security -Wno-unused")

product-mini/platforms/linux/CMakeLists.txt

@@ -145,7 +145,7 @@ set_target_properties (vmlib PROPERTIES POSITION_INDEPENDENT_CODE ON)
 
 set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--gc-sections")
 
-set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wformat -Wformat-security -Wshadow")
+set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wformat -Wformat-security -Wshadow -fvisibility=hidden")
 # set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wconversion -Wsign-conversion")
 
 set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wformat -Wformat-security -Wno-unused")