Fix #4421: Add -C DIR flag

[archie2x]

See #4421

Implementation is copied from BigGo 1.22.5 with minor modification.

https://github.com/golang/go/blob/d79c350916c637de911d93af689a5e4e7ab5a5bb/src/cmd/go/main.go#L330

[deadprogram]

Hello @archie2x thanks for the PR. Just wondering if you could add a test of some kind, perhaps?

[archie2x]

Hello @archie2x thanks for the PR. Just wondering if you could add a test of some kind, perhaps?

Absolutely. A test didn't originally seem obvious to me but I think something as simple as tinygo build -C testdata testprogram.go should work. I'll put that together. Should I rebase?

[deadprogram]

Should I rebase?

Yes, please!

[archie2x]

Hello @archie2x thanks for the PR. Just wondering if you could add a test of some kind, perhaps?

Absolutely. A test didn't originally seem obvious to me but I think something as simple as tinygo build -C testdata testprogram.go should work. I'll put that together. Should I rebase?

Please let me know if the attached tests suffice for now. I wasn't familiar with the test framework here. I think there may be some opportunity to cleanup how temp directories are used? I'm getting quite a few in my /tmp when I try to run everything locally.

[dgryski]

LGTM. CI passes on Windows now.

[deadprogram]

Thank you very much for the PR @archie2x and to @dgryski for review.

Now squash/merging.