Bad file descriptor problem

For Developers
1

I often find the following error when I compile the project
/bin/sh: 1: 8: Bad file descriptor


ifeq ($(findstring s,$(OPENWRT_VERBOSE)),)  
  define MESSAGE                                              ########### 
	printf "$(_Y)%s$(_N)\n" "$(1)" >&8
  endef

  ifeq ($(QUIET),1)
    ifneq ($(CURDIR),$(TOPDIR))
      _DIR:=$(patsubst $(TOPDIR)/%,%,${CURDIR})
    else
      _DIR:=
    endif
   ## I found it was caused by the following line, and I never understood why use >&8, 
    _NULL:=$(if $(MAKECMDGOALS),$(shell \
		$(call MESSAGE, make[$(MAKELEVEL)]$(if $(_DIR), -C $(_DIR)) $(MAKECMDGOALS)); \
    ))
    SUBMAKE=$(MAKE)
  else
    SILENT:=>/dev/null $(if $(findstring w,$(OPENWRT_VERBOSE)),,2>&1)
    export QUIET:=1
    SUBMAKE=cmd() { $(SILENT) $(MAKE) -s "$$@" < /dev/null || { echo "make $$*: build failed. Please re-run make with -j1 V=s or V=sc for a higher verbosity level to see what's going on"; false; } } 8>&1 9>&2; cmd
  endif

  .SILENT: $(MAKECMDGOALS)
else
  SUBMAKE=$(MAKE) -w
  define MESSAGE
    printf "%s\n" "$(1)"
  endef
endif