Change in coreboot[master]: Makefile.inc: add .map target

[Nico Huber (Code Review)]

Attention is currently required from: Felix Held.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/51385 )

Change subject: Makefile.inc: add .map target
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Patch Set 1:

(1 comment)

File Makefile.inc:

https://review.coreboot.org/c/coreboot/+/51385/comment/45d1b8d2_ab723b73 
PS1, Line 780: $(objcbfs)/%.elf $(objcbfs)/%.map: $(objcbfs)/%.debug
> Thanks for that explanation. I was always under the impression that it was a "group". […]

What we sometimes do to settle such cases: Add a dummy rule for the
additional file that depends on the primary output, e.g.

$(objcbfs)/%.map: $(objcbfs)/%.elf
            true

or if one wants to ensure that the modification dates are in order:

$(objcbfs)/%.map: $(objcbfs)/%.elf
            touch $@

Haven't tested the latter, though. One thing was tested: the recipe
mustn't be empty (cf. CB:28198).