Undo no arg check in 1990/theorem

As part of the redefinition of INABIAF one of the segfault fixes has
been undone. The others were necessary as part of making the entry work
in modern systems but this one should not have been done. Instead the
Makefile and README.md warn about it.

I did however discover another bug with this entry that makes one of the
generated programs not work. I documented that in bugs.md and I'll look
at it another time.

1990/theorem/Makefile

@@ -133,6 +133,7 @@ all: data ${TARGET}
 	supernova deep_magic magic charon pluto
 
 ${PROG}: ${PROG}.c
+	@echo "NOTE: this entry will segfault on no arg specified."
 	${CC} ${CFLAGS} $< -o $@ ${LIBS}
 
 sorter.c: ${PROG} ${PROG}.c