Add alt supplementary program to 2001/anonymous

Running make alt will compile the anonymous.ten.c without specifying
-m32: whether it'll end up being 64-bit or not would depend on the
system but it'll be saved as anonymous.ten.64 anyway.

The try.me.sh script will run this program directly, skipping the entry
itself, if the anonymous.ten.c cannot be compiled as a 32-bit binary.

Updated .gitignore.

2001/anonymous/Makefile

@@ -117,10 +117,10 @@ PROG= ${ENTRY}
 #
 OBJ= ${PROG}.o
 DATA=
-TARGET= ${PROG} ${PROG}.ten
+TARGET= ${PROG} ${PROG}.ten ${PROG}.ten.64
 #
-ALT_OBJ= 
-ALT_TARGET=
+ALT_OBJ= ${PROG}.ten.64.o
+ALT_TARGET= ${PROG}.ten.64
 
 
 #################
@@ -156,6 +156,11 @@ ${PROG}.ten: ${PROG}.ten.c
 	@echo
 	${CC} ${CFLAGS} -m32 $< -o $@ ${LIBS}
 
+${PROG}.ten.64: ${PROG}.ten.c
+	@echo "WARNING: the file created by this rule will NOT work with the entry itself;"
+	@echo "this is because it works ONLY on 32-bit ELF binaries! This however at least"
+	@echo "lets you see the supplementary program in action."
+	${CC} ${CFLAGS} $< -o $@ ${LIBS}
 
 # alternative executable
 #