set default value of WAMR_BUILD_REF_TYPES to 1 in standalone cases (#4227)

- set default value of WAMR_BUILD_REF_TYPES to 1 in CMakeLists.txt

tests/standalone/test-running-modes/c-embed/CMakeLists.txt

@@ -11,10 +11,10 @@
 # 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.
-project(c_embed_test)
-
 cmake_minimum_required(VERSION 3.14)
 
+project(c_embed_test)
+
 include(CheckPIESupported)
 
 string (TOLOWER ${CMAKE_HOST_SYSTEM_NAME} WAMR_BUILD_PLATFORM)
@@ -34,6 +34,11 @@ set(WAMR_BUILD_LIBC_WASI 1)
 set(WAMR_BUILD_SIMD 1)
 set(WAMR_ROOT_DIR ${CMAKE_CURRENT_LIST_DIR}/../../../..)
 
+if (NOT DEFINED WAMR_BUILD_REF_TYPES)
+  # Enable reference types by default
+  set (WAMR_BUILD_REF_TYPES 1)
+endif ()
+
 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}")
 if (NOT WAMR_BUILD_PLATFORM STREQUAL "darwin")
   set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--gc-sections -pie -fPIE")