diff --git a/toolchain_config.gni b/toolchain_config.gni
index 9442eb52fa7f025498fb55465140ef9ac36141e6..5ed5f7e16a571c261b209da44c7d7ba488710abe 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
 }