Add note about 1986/wall.alt.c

It was added so one can see just how different the C language was at the
time. Well see without having to look at the archive.

1986/wall/README.md

@@ -16,7 +16,9 @@ We used a patch provided by [Yusuke Endoh](/winners.html#Yusuke_Endoh) to make
 this work with gcc (in particular the patch uses `strdup()` on two strings).
 Thank you Yusuke! [Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) fixed
 this so that it does not require `-traditional-cpp`. This took a fair bit of
-tinkering as this entry *is* strange. Thank you Cody for your assistance!
+tinkering as this entry *is* strange. The original code is provided to allow one
+to easily see how different C was in these days. See below for details. Thank
+you Cody for your assistance!
 
 ## To use: