Index: src/libmawk/vio_fifo.c
===================================================================
diff --git a/src/libmawk/vio_fifo.c b/src/libmawk/vio_fifo.c
--- a/src/libmawk/vio_fifo.c	(revision 1326)
+++ b/src/libmawk/vio_fifo.c	(revision 1327)
@@ -10,6 +10,8 @@
 #include "vio_fifo.h"
 #include "memory.h"
 
+const mawk_vio_imp_t mawk_vio_fifo_imp;
+
 mawk_vio_t *mawk_vio_fifo_open(mawk_state_t *MAWK, const char *name, mawk_vio_open_mode_t mode)
 {
 	mawk_vio_fifo_t *v;
Index: src/libmawk/vio_fifo.h
===================================================================
diff --git a/src/libmawk/vio_fifo.h b/src/libmawk/vio_fifo.h
--- a/src/libmawk/vio_fifo.h	(revision 1326)
+++ b/src/libmawk/vio_fifo.h	(revision 1327)
@@ -14,7 +14,7 @@
 	int eof_from_app;       /* 1 if there won't be more from the app or the app won't accept more data */
 } mawk_vio_fifo_t;
 
-const mawk_vio_imp_t mawk_vio_fifo_imp;
+extern const mawk_vio_imp_t mawk_vio_fifo_imp;
 
 mawk_vio_t *mawk_vio_fifo_open(mawk_state_t *MAWK, const char *name, mawk_vio_open_mode_t mode);