Change in flashrom[master]: Makefile: build shared usb code only when needed by programmer

[Edward O'Callaghan (Code Review)]

Attention is currently required from: Nico Huber, Thomas Heijligen.
Edward O'Callaghan has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/62832 )

Change subject: Makefile: build shared usb code only when needed by programmer
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Patch Set 2:

(1 comment)

Patchset:

PS1:
> Yes, that is correct. I just want to make sure we are not too pedantic […]

While I can see the reasoning for this and it makes sense I have a supplementary argument to Nico's diff reduction maintenance one.

I would rather we go the other way as by reducing both build system and pre-processor cyclomatic complexity means that the compiler is more likely to see a more consistent picture of the tree as the moving window of changes sweeps HEAD. Furthermore, it lets the linker in the toolchain do it's job and cull symbols that are not required in the resulting binary rather than trying to pre-optimise at the build system level. The associativity property should rather be done at the build target level to again, let the build system do its job of relationship management best.

Hopefully my thinking makes sense here Thomas, however thanks for the different prospective too!