Remove build.rs

[jiangliu]

Afeter commit 5820bf6, build.rs has no use anymore, so remove.

[zanieb]

Where is the unwind feature turned on then?

[jiangliu]

Where is the unwind feature turned on then?

When using py-spy as rust library crate, we can enable unwind feature when specifying the dependency.
When building py-spy as a binary, we can enable unwind with cargo cmdline options.
Unfortunately seems that cargo doesn't support enable features for specific target/arch yet.

BTW, there's no code make use of #[cfg(unwind)] anymore, there have all been converted to #[cfg(feature = "unwind")], so the build.rs becomes useless.

[zanieb]

Yeah but that pull request didn't actually update anything to use the unwind feature right? So it just ended up turning it off?

Unfortunately seems that cargo doesn't support enable features for specific target/arch yet.

Yeah that's why it's written as a custom cfg and we'll probably want to revert the feature change and do
zanieb@045846a instead

Alternatively, we need to at least specify the feature per platform during builds. Edit: Looks like @benfred made this change in #691.

I don't have strong feelings about which pattern to use. It depends how critical having unwind enabled is, I guess, since people will undoubtably build and test without it enabled accidentally when it's an opt-in feature.

[jiangliu]

Yeah but that pull request didn't actually update anything to use the unwind feature right? So it just ended up turning it off?

Unfortunately seems that cargo doesn't support enable features for specific target/arch yet.

Yeah that's why it's written as a custom cfg and we'll probably want to revert the feature change and do zanieb@045846a instead

Alternatively, we need to at least specify the feature per platform during builds. Edit: Looks like @benfred made this change in #691.

I don't have strong feelings about which pattern to use. It depends how critical having unwind enabled is, I guess, since people will undoubtably build and test without it enabled accidentally when it's an opt-in feature.

Hi @zanieb,
I have worked out a draft patch to make unwind as default feature, which may help to address your concern:) I would like to make feature unwind work as expect so user can disable unwind when needed.