b2/: simplified and corrected logic behind relop_redundant

We now generate the operator map algorithmically, which is a bit less
classy than solving the logical equations, but easier to get right.

Also renamed the somewhat vague "redundant" to "unreachable".

b2/Makefile

@@ -79,11 +79,17 @@ y.tab.o:	y.tab.c
 		$(CC) -c $(CFLAGS) $*.c -o $*.o
 		$(call MKDEP, $*)
 
+relop.o:	unreachable.inc
+
+unreachable.inc: genredmap.pl
+		$(GEN) ./$< 0 >$@ || { rm -f $@; exit 1; }
+
 -include $(OBJS:.o=.d)
 
 clean:
 		rm -f $(OBJS) $(OBJS:.o=.d)
 		rm -f lex.yy.c y.tab.c y.tab.h y.output
+		rm -f redmap.inc
 
 spotless:	clean
 		rm -f boom