libbb unicode: comment out usused function and unused parameter

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/coreutils/cal.c b/coreutils/cal.c
index ef5dbea..f18c161 100644
--- a/coreutils/cal.c
+++ b/coreutils/cal.c
@@ -138,7 +138,7 @@
 			if (julian)
 				*hp++ = ' ';
 			{
-				char *two_wchars = unicode_conv_to_printable_fixedwidth(NULL, buf, 2);
+				char *two_wchars = unicode_conv_to_printable_fixedwidth(/*NULL,*/ buf, 2);
 				strcpy(hp, two_wchars);
 				free(two_wchars);
 			}