workaround for segfault in std.net.curl.Curl.shutdown() on exit

src/main.d

@@ -143,6 +143,9 @@ void main(string[] args)
 			}
 		}
 	}
+
+	// workaround for segfault in std.net.curl.Curl.shutdown() on exit
+	onedrive.http.shutdown();
 }
 
 // try to synchronize the folder three times

src/onedrive.d

@@ -35,7 +35,7 @@ final class OneDriveApi
 	private string clientId, clientSecret;
 	private string refreshToken, accessToken;
 	private SysTime accessTokenExpiration;
-	private HTTP http;
+	/* private */ HTTP http;
 
 	void delegate(string) onRefreshToken; // called when a new refresh_token is received