diff --git a/clib/culfw.c b/clib/culfw.c
index d99a71b..b32cd55 100644
--- a/clib/culfw.c
+++ b/clib/culfw.c
@@ -10,6 +10,7 @@
 #include "arch.h"
 #include "display.h"
 #include "fncollection.h"
+#include "registry.h"
 #include "led.h"		// ledfunc
 #include "ringbuffer.h"
 #include "rf_receive.h"
diff --git a/clib/ttydata.c b/clib/ttydata.c
index 8d60d58..fba8889 100644
--- a/clib/ttydata.c
+++ b/clib/ttydata.c
@@ -3,6 +3,7 @@
 #include <avr/pgmspace.h>
 
 void (*input_handle_func)(uint8_t channel);
+void (*output_flush_func)(void);
 
 rb_t TTY_Tx_Buffer;
 rb_t TTY_Rx_Buffer;
diff --git a/clib/ttydata.h b/clib/ttydata.h
index f38bd8a..0ca2111 100644
--- a/clib/ttydata.h
+++ b/clib/ttydata.h
@@ -11,8 +11,8 @@ typedef struct _fntab {
 void analyze_ttydata(uint8_t channel);
 uint8_t callfn(char *buf);
 
-void (*input_handle_func)(uint8_t channel);
-void (*output_flush_func)(void);
+extern void (*input_handle_func)(uint8_t channel);
+extern void (*output_flush_func)(void);
 
 extern rb_t TTY_Tx_Buffer;
 extern rb_t TTY_Rx_Buffer;
diff --git a/clib/usb.h b/clib/usb.h
index b6094cc..824b088 100644
--- a/clib/usb.h
+++ b/clib/usb.h
@@ -4,8 +4,8 @@
 #include "Descriptors.h"
 #include <LUFA/Drivers/USB/USB.h>
 
-USB_ClassInfo_CDC_Device_t VirtualSerial1_CDC_Interface;
-USB_ClassInfo_CDC_Device_t VirtualSerial2_CDC_Interface;
+extern USB_ClassInfo_CDC_Device_t VirtualSerial1_CDC_Interface;
+extern USB_ClassInfo_CDC_Device_t VirtualSerial2_CDC_Interface;
 
 void usb_init(void);
 void usb_task(void);