[M] Change in flashrom[master]: serial: Add Darwin/macOS support for custom and >230400 baudrates

[Peter Stuge (Code Review)]

Attention is currently required from: Thomas Heijligen, Name of user not set #1004601.

Peter Stuge has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/70571 )

Change subject: serial: Add Darwin/macOS support for custom and >230400 baudrates
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Patch Set 4:

(1 comment)

File serial.c:

https://review.coreboot.org/c/flashrom/+/70571/comment/661b4ee7_f74835a0 
PS4, Line 78: #if !IS_DARWIN
> why guard the higher boudrates additionally for darwin? When looking at https://opensource.apple. […]

I understand that this can feel redundant.

I added the explicit guard to make sure that higher baudrates will always use the custom ioctl, because the kernel will probably never support them even if the defines are added some time.

I was considering a later patch to have a single common implementation of use_custom_baud() but I removed that from this patch series.

If the explicit guard in serial.c is a no-go then I'd add the condition to custom_baud_darwin.c:use_custom_baud() instead, moving away from the possibility to have one common use_custom_baud() across platforms.

Is that preferable? I'm fine either way. Please advise.