bpo-32670: Enforce PEP 479. (#5327)

diff --git a/Python/future.c b/Python/future.c
index 53faa6b..ade647f 100644
--- a/Python/future.c
+++ b/Python/future.c
@@ -41,7 +41,7 @@
         } else if (strcmp(feature, FUTURE_BARRY_AS_BDFL) == 0) {
             ff->ff_features |= CO_FUTURE_BARRY_AS_BDFL;
         } else if (strcmp(feature, FUTURE_GENERATOR_STOP) == 0) {
-            ff->ff_features |= CO_FUTURE_GENERATOR_STOP;
+            continue;
         } else if (strcmp(feature, FUTURE_ANNOTATIONS) == 0) {
             ff->ff_features |= CO_FUTURE_ANNOTATIONS;
         } else if (strcmp(feature, "braces") == 0) {