Remove 1986/wall alt code

The alt code was just a patched (by Yusuke Endoh) version (two strings
were strdup()d) that still required -traditional-cpp. He is still
credited in the thanks file but one can do make diff_orig_prog to see
what was changed to make it not require -traditional-cpp and Yusuke's
fix is there too. The thanks file details what I had to do to make it
work without -traditional-cpp and his change is still there as well. It
seemed to serve no purpose to have an alt version that requires one to
use -traditional-cpp when one can just look at the original code if they
want to see what it was like back in 1986.

thanks-for-help.md

@@ -419,16 +419,13 @@ code](/1986/wall/wall.orig.c) to see how different C was in 1986, as well as
 below.
 
 [Yusuke](#yusuke) originally patched this to use `strdup()` on two strings and this let it
-work with gcc but it still required `-traditional-cpp`. The [alternate
-code](/1986/wall/wall.alt.c) is the version patched by Yusuke should you wish to
-try it with a compiler that has the `-traditional-cpp`. See the README.md file
-for details.
+work with gcc but it still required `-traditional-cpp`.
 
 If you'd like to see the difference between the version that requires
 `-traditional-cpp` and the fixed version, try:
 
 ```sh
-cd 1986/wall ; make diff_alt_prog
+cd 1986/wall ; make diff_orig_prog
 ```
 
 Some of the changes required:
@@ -495,6 +492,9 @@ Some of the changes required:
 
 	    :system(ccc(";kkt -oa, dijszdijs QQ"));return
 
+- And of course as noted two strings had to be `strdup()`d.
+
+There might have been other changes as well.
 
 
 # <a name="1987"></a>1987