fix build.rs src/ behavior

[nick1udwig]

Problem

We don't rebuild core processes when their src/ is changed.

Solution

When we are inside a directory that is contained in rerun_files, print all entries therein.

Docs Update

N/A

Notes

None

[dr-frmr]

@nick1udwig is there an amortizeable performance cost to all this..? or is it negligible/cost of doing business

[nick1udwig]

So the "correct" behavior is that on a rebuild we go and try to kit build all the packages/. I THINK this PR should do that, but I've thought like 5 iterations of build.rs should do that so...

In any case, kit build does a good job of rebuilding only when necessary. You can experience this yourself when you kit b a package: first time build takes a while; second time with no changes is nearly instant; third time with changes is usually 1-2 seconds on my machine.

[dr-frmr]

Oh no I just meant performance of traversing all the directories to find changes and cargo-print them. I suppose that's meaningless compared to build time itself.

[dr-frmr]

LGTM

[nick1udwig]

Oh no I just meant performance of traversing all the directories to find changes and cargo-print them. I suppose that's meaningless compared to build time itself.

Ah, I see. Yeah, I think you are correct: small wrt overall build time.