[U-Boot] what means "obj- := __dummy__.o"?

[Robert P. J. Day]

  i'm feeling particularly stupid today in not understanding some of
the things i'm running across. just tripped over this in
board/spear/common/Makefile:

  ...
  ifdef CONFIG_SPL_BUILD
  # necessary to create built-in.o
  obj- := __dummy__.o                       <--- ??????
  else
  ...

i've never seen that syntax before, and there's just a bit of it in
the entire tree:

$ grep -r "obj- " *
arch/arm/cpu/arm1176/Makefile:obj- += dummy.o
arch/arm/cpu/Makefile:obj- += dummy.o
board/samsung/smdkv310/Makefile:obj- := __dummy__.o
board/samsung/origen/Makefile:obj- := __dummy__.o
board/spear/x600/Makefile:obj- := __dummy__.o
board/spear/common/Makefile:obj- := __dummy__.o
board/freescale/common/Makefile:obj- := __dummy__.o
board/varisys/common/Makefile:obj- := __dummy__.o
$

  what does that mean?

rday

-- 

========================================================================
Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
========================================================================