bash: add run make generated builtin files.

N/A

1. comment builtins/Makefile such as:
.def.o:
	$(RM) $@
	./$(MKBUILTINS) $(DIRECTDEFINE) $<
	$(CC) -c $(CCFLAGS) $*.c || ( $(RM) $*.c ; exit 1 )
	$(RM) $*.c  # this line is our commented
2. make
3. generated files such as:
	bash-4.3/builtins/alias.c
	bash-4.3/builtins/bind.c
	bash-4.3/builtins/break.c
	bash-4.3/builtins/builtext.h
	bash-4.3/builtins/builtin.c
	bash-4.3/builtins/builtins.c
	bash-4.3/builtins/caller.c
	bash-4.3/builtins/cd.c
	bash-4.3/builtins/colon.c
	bash-4.3/builtins/command.c
	bash-4.3/builtins/complete.c
	bash-4.3/builtins/declare.c
	bash-4.3/builtins/echo.c
	bash-4.3/builtins/enable.c
	bash-4.3/builtins/eval.c
	bash-4.3/builtins/exec.c
	bash-4.3/builtins/exit.c
	bash-4.3/builtins/fc.c
	bash-4.3/builtins/fg_bg.c
	bash-4.3/builtins/getopts.c
	bash-4.3/builtins/hash.c
	bash-4.3/builtins/help.c
	bash-4.3/builtins/history.c
	bash-4.3/builtins/jobs.c
	bash-4.3/builtins/kill.c
	bash-4.3/builtins/let.c
	bash-4.3/builtins/mapfile.c
	bash-4.3/builtins/pipesize.h
	bash-4.3/builtins/printf.c
	bash-4.3/builtins/pushd.c
	bash-4.3/builtins/read.c
	bash-4.3/builtins/return.c
	bash-4.3/builtins/set.c
	bash-4.3/builtins/setattr.c
	bash-4.3/builtins/shift.c
	bash-4.3/builtins/shopt.c
	bash-4.3/builtins/source.c
	bash-4.3/builtins/suspend.c
	bash-4.3/builtins/test.c
	bash-4.3/builtins/times.c
	bash-4.3/builtins/trap.c
	bash-4.3/builtins/type.c
	bash-4.3/builtins/ulimit.c
	bash-4.3/builtins/umask.c
	bash-4.3/builtins/wait.c
	bash-4.3/lsignames.h
	bash-4.3/pathnames.h
	bash-4.3/signames.h
	bash-4.3/syntax.c
	bash-4.3/version.h

Signed-off-by: liminghao <liminghao@xiaomi.com>