[S] Change in coreboot[master]: Makefile.inc: Optimize even more for size with clang

[Julius Werner (Code Review)]

Attention is currently required from: Martin L Roth, Arthur Heymans.

Julius Werner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/70159 )

Change subject: Makefile.inc: Optimize even more for size with clang
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Patch Set 1:

(1 comment)

Patchset:

PS1: 
Is this actually what we want? My understanding is that Oz is supposed to optimize for the smallest possible size no matter how much it increases execution time. We do have some pressure for code size that's larger than what userspace programs normally have (due to limited flash space and SPI loading times), but that doesn't mean execution time doesn't matter for us. If the goal is to actually switch to Oz everywhere (with GCC 12), I think we should have some analysis (across architectures) to understand the practical impact on boot times first.