--- a/program/psiconv/psiconv.c
+++ b/program/psiconv/psiconv.c
@@ -41,6 +41,8 @@
 #include "gen.h"
 #include "psiconv.h"
 
+psiconv_list fileformat_list;
+
 static void print_help(void);
 static void print_version(void);
 static void strtoupper(char *str);
--- a/program/psiconv/psiconv.h
+++ b/program/psiconv/psiconv.h
@@ -31,6 +31,6 @@
   output_function *output;
 } *psiconv_fileformat;
 
-psiconv_list fileformat_list; /* of struct psiconv_fileformat */
+extern psiconv_list fileformat_list; /* of struct psiconv_fileformat */
 
 #endif /* PSICONV_GEN_H */