Fix -fno-common build failure.

Index: testsuite/t_loadwords.c
--- testsuite/t_loadwords.c.orig
+++ testsuite/t_loadwords.c
@@ -52,6 +52,7 @@ extern void	freewords(void);
 extern int	loadwords(char *);
 
 extern char	worddir[MAXPATHLEN];
+extern struct rawdata  words;
 
 int
 main(void)
