diff --git a/toolchain_config.gni b/toolchain_config.gni
index 6641441e555b4b6f884db08df835538a0d7ac90c..e3b687a3b3e1ee2b26963bdbb23c1610633e1620 100644
--- a/toolchain_config.gni
+++ b/toolchain_config.gni
@@ -11,6 +11,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+if (!defined(enable_cmc_gc)) {
+  enable_cmc_gc = false
+}
+
 if (!defined(ark_standalone_build)) {
   ark_standalone_build = false
 }