Fixup some silly prototype warnings
diff --git a/coreutils/tr.c b/coreutils/tr.c
index 2665d92..e2a4ef6 100644
--- a/coreutils/tr.c
+++ b/coreutils/tr.c
@@ -44,7 +44,7 @@
 static char *pinvec, *poutvec;
 
 
-static void convert()
+static void convert(void)
 {
 	short read_chars = 0;
 	short c, coded;