some changes xcode 9 suggested

Author: alehed

External/libextobjc/extobjc/EXTScope.h

@@ -88,7 +88,7 @@
     _Pragma("clang diagnostic pop")
 
 /*** implementation details follow ***/
-typedef void (^gt_ext_cleanupBlock_t)();
+typedef void (^gt_ext_cleanupBlock_t)(void);
 
 void gt_ext_executeCleanupBlock (__strong gt_ext_cleanupBlock_t *block);
 

ObjectiveGit/GTRepository+RemoteOperations.m

@@ -266,9 +266,9 @@ - (BOOL)pushRefspecs:(NSArray *)refspecs toRemote:(GTRemote *)remote withOptions
 	};
 
 	git_remote_callbacks remote_callbacks = GIT_REMOTE_CALLBACKS_INIT;
-	remote_callbacks.credentials = (credProvider != nil ? GTCredentialAcquireCallback : NULL),
+	remote_callbacks.credentials = (credProvider != nil ? GTCredentialAcquireCallback : NULL);
 	remote_callbacks.push_transfer_progress = GTRemotePushTransferProgressCallback;
-	remote_callbacks.payload = &connectionInfo,
+	remote_callbacks.payload = &connectionInfo;
 
 	gitError = git_remote_connect(remote.git_remote, GIT_DIRECTION_PUSH, &remote_callbacks, NULL, NULL);
 	if (gitError != GIT_OK) {

ObjectiveGit/GTRepository.m

@@ -624,7 +624,7 @@ - (BOOL)isHEADUnborn {
 	return (BOOL)git_repository_head_unborn(self.git_repository);
 }
 
-- (NSString *)preparedMessageWithError:(NSError **)error {
+- (NSString *)preparedMessageWithError:(NSError * __autoreleasing *)error {
 	void (^setErrorFromCode)(int) = ^(int errorCode) {
 		if (errorCode == 0 || errorCode == GIT_ENOTFOUND) {
 			// Not an error.