Improve 1984/mullender alt code

Using 2018/mills (an amazing entry) with trial and error I was able to
determine the approximate speed that the :-) moved across the screen and
now the alt code moves at almost exactly (I believe, at least) that
speed.

The mullender.alt2.c was deleted; instead that became mullender.alt.c.
This is because (I believe but have not confirmed) that the original did
not exit after it timed out and there's no need to have two alt versions
when they're so similar. One is good enough and the obvious choice is
the one that can keep going on.

.gitignore updated.

1984/mullender/Makefile

@@ -112,8 +112,8 @@ OBJ= ${PROG}.o
 DATA=
 TARGET= ${PROG}
 #
-ALT_OBJ= ${PROG}.alt.o ${PROG}.alt2.o
-ALT_TARGET= ${PROG}.alt ${PROG}.alt2
+ALT_OBJ= ${PROG}.alt.o
+ALT_TARGET= ${PROG}.alt
 
 
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