Separate the posix part of the c-ares driver
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index 399368bab..ca6df16 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -785,6 +785,7 @@
                       'src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc',
                       'src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc',
                       'src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc',
+                      'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc',
                       'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc',
                       'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc',
                       'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc',