diff -up megaglest-3.13.0/source/shared_lib/include/feathery_ftp/ftpTypes.h.orig megaglest-3.13.0/source/shared_lib/include/feathery_ftp/ftpTypes.h
--- megaglest-3.13.0/source/shared_lib/include/feathery_ftp/ftpTypes.h.orig	2020-03-30 13:56:49.360323060 -0300
+++ megaglest-3.13.0/source/shared_lib/include/feathery_ftp/ftpTypes.h	2020-03-30 13:58:21.924743049 -0300
@@ -69,7 +69,7 @@ typedef uint16_t port_t;
 extern "C" {
 #endif
 
-int VERBOSE_MODE_ENABLED;
+extern int VERBOSE_MODE_ENABLED;
 
 typedef ip_t (*ftpFindExternalFTPServerIpType)(ip_t clientIp);
 typedef void (*ftpAddUPNPPortForwardType)(int internalPort, int externalPort);
@@ -77,11 +77,11 @@ typedef void (*ftpRemoveUPNPPortForwardT
 typedef int (*ftpIsValidClientType)(ip_t clientIp);
 typedef int (*ftpIsClientAllowedToGetFileType)(ip_t clientIp, const char *username, const char *filename);
 
-ftpFindExternalFTPServerIpType	ftpFindExternalFTPServerIp;
-ftpAddUPNPPortForwardType		ftpAddUPNPPortForward;
-ftpRemoveUPNPPortForwardType	ftpRemoveUPNPPortForward;
-ftpIsValidClientType            ftpIsValidClient;
-ftpIsClientAllowedToGetFileType ftpIsClientAllowedToGetFile;
+extern ftpFindExternalFTPServerIpType	ftpFindExternalFTPServerIp;
+extern ftpAddUPNPPortForwardType		ftpAddUPNPPortForward;
+extern ftpRemoveUPNPPortForwardType	ftpRemoveUPNPPortForward;
+extern ftpIsValidClientType            ftpIsValidClient;
+extern ftpIsClientAllowedToGetFileType ftpIsClientAllowedToGetFile;
 
 #ifdef	__cplusplus
 }
diff -up megaglest-3.13.0/source/shared_lib/sources/feathery_ftp/ftpRuntime.c.orig megaglest-3.13.0/source/shared_lib/sources/feathery_ftp/ftpRuntime.c
--- megaglest-3.13.0/source/shared_lib/sources/feathery_ftp/ftpRuntime.c.orig	2020-03-30 13:56:56.412355058 -0300
+++ megaglest-3.13.0/source/shared_lib/sources/feathery_ftp/ftpRuntime.c	2020-03-30 13:58:30.524782070 -0300
@@ -30,6 +30,13 @@
 #include "ftp.h"
 #include "ftpMessages.h"
 
+int VERBOSE_MODE_ENABLED;
+
+ftpFindExternalFTPServerIpType  ftpFindExternalFTPServerIp;
+ftpAddUPNPPortForwardType               ftpAddUPNPPortForward;
+ftpRemoveUPNPPortForwardType    ftpRemoveUPNPPortForward;
+ftpIsValidClientType            ftpIsValidClient;
+ftpIsClientAllowedToGetFileType ftpIsClientAllowedToGetFile;
 
 /**
  * @brief server-sockets that listens for incoming connections