Extern-ify symbols so they don't collide

src/python/src/grpc/_adapter/_call.h

@@ -70,7 +70,7 @@ typedef struct {
   grpc_call *c_call;
 } Call;
 
-PyTypeObject pygrpc_CallType;
+extern PyTypeObject pygrpc_CallType;
 
 int pygrpc_add_call(PyObject *module);
 

src/python/src/grpc/_adapter/_channel.h

@@ -42,7 +42,7 @@ typedef struct {
   grpc_channel *c_channel;
 } Channel;
 
-PyTypeObject pygrpc_ChannelType;
+extern PyTypeObject pygrpc_ChannelType;
 
 int pygrpc_add_channel(PyObject *module);
 

src/python/src/grpc/_adapter/_client_credentials.h

@@ -42,7 +42,7 @@ typedef struct {
   grpc_credentials *c_client_credentials;
 } ClientCredentials;
 
-PyTypeObject pygrpc_ClientCredentialsType;
+extern PyTypeObject pygrpc_ClientCredentialsType;
 
 int pygrpc_add_client_credentials(PyObject *module);
 

src/python/src/grpc/_adapter/_completion_queue.h

@@ -42,7 +42,7 @@ typedef struct {
   grpc_completion_queue *c_completion_queue;
 } CompletionQueue;
 
-PyTypeObject pygrpc_CompletionQueueType;
+extern PyTypeObject pygrpc_CompletionQueueType;
 
 int pygrpc_add_completion_queue(PyObject *module);
 

src/python/src/grpc/_adapter/_server_credentials.h

@@ -42,7 +42,7 @@ typedef struct {
   grpc_server_credentials *c_server_credentials;
 } ServerCredentials;
 
-PyTypeObject pygrpc_ServerCredentialsType;
+extern PyTypeObject pygrpc_ServerCredentialsType;
 
 int pygrpc_add_server_credentials(PyObject *module);