Assembly preprocessor (rpp) improvements

[jhand2]

rpp does not currently support multiline macros such as

#define MACRO some \
    stuff

This should be an easy thing to add

[pdogr]

Hi!
I've tried adding this feature in #538. I was not sure if we should preserve the exact structure (escaped newlines) in macro definition, though this would really depend on whether the assembly has a free-form syntax?

[jhand2]

Thanks! It's worth noting that since #504 was resolved, oreboot assembly no longer uses rpp to insert macros. Apologies for not updating this issue.

That says, rpp is still fun endeavor and I'll take a look at the PR.

[pdogr]

Sorry! I should've asked before picking this up.

[jhand2]

No problem 😄 I might move rpp into it's own repo/crate at some point.