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.

1986/wall/Makefile

@@ -117,8 +117,8 @@ OBJ= ${PROG}.o
 DATA=
 TARGET= ${PROG}
 #
-ALT_OBJ= ${PROG}.alt.o
-ALT_TARGET= ${PROG}.alt
+ALT_OBJ=
+ALT_TARGET=
 
 #################
 # build the entry
@@ -140,9 +140,6 @@ ${PROG}: ${PROG}.c
 alt: ${ALT_TARGET}
 	@${TRUE}
 
-${PROG}.alt: ${PROG}.alt.c
-	${CC} ${CFLAGS} $< -o $@ ${LDFLAGS}
-
 # data files
 #
 data: ${DATA}