[coreboot-gerrit] Change in ...coreboot[master]: string.h: allow to compile strdup in romstage

[Nico Huber (Code Review)]

Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/30844 )

Change subject: string.h: allow to compile strdup in romstage
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Patch Set 5:
> https://qa.coreboot.org/job/coreboot-gerrit/87667/ : UNSTABLE

It seems everyone has its own ASSERT() defined. I see two ways
to fix it (both not in the scope of this change).

1. don't define ASSERT() in assert.h (e.g. rename it to _ASSERT()). existing calls should call the standard assert()
2. move dead_code() into its own header file