Supporting the nightly flag -Zmultitarget

[TheOnlyArtz]

First of all I want to say thank you for this incredible tool, it made our work so much easier.

As a part of our pipe line we need to build our program to multiple targets, recently a change has been made to the cargo cli allowing to pass a flag called multitarget which makes it possible to compile to multiple targets all at once.

The proposed changes follow the way the cargo build CLI works, see:
https://github.dev/rust-lang/cargo/blob/06b9d31743210b788b130c8a484c2838afa6fc27/src/bin/cargo/commands/build.rs

    fn arg_target_triple(self, target: &'static str) -> Self {
        self._arg(multi_opt("target", "TRIPLE", target))
    }

pub fn multi_opt(name: &'static str, value_name: &'static str, help: &'static str) -> Arg<'static> {
    opt(name, help)
        .value_name(value_name)
        .multiple_occurrences(true)
}

suggesting that target should infact be a flag which may occur N >= 1 amount of times.

This pull request makes it possible to run the next:
cargo-zigbuild.exe build -Zmultitarget --target x86_64-pc-windows-msvc --target x86_64-unknown-linux-musl --release

[TheOnlyArtz]

I see where the issue arises, the loop in the method which constructs the process command is pretty much useless as it just overrides the previous iteration.

Although, the dynamic environment variables are related to the linker, and they are being bound to a specific target which seems ok.

I can't have an idea why the CI would fail that much really...

What would be a sensible approach for multi target builds? Multi threading? What do you think? @messense

[messense]

error: linking with cc failed: exit status: 1

Looks like it's not using our linker wrapper script.

[messense]

CC_aarch64_unknown_linux_gnu = None

It's not working, maybe you can add some println!s to debug it.

[TheOnlyArtz]

It just compiled fine on my end, I don't know why the CI would fail, it also looks for CC_{lower_cased_target} ? It's case sensitive ain't it?

PS C:\Users\amitkatz\Desktop\cargo-zigbuild> cargo r zigbuild --target aarch64-unknown-linux-gnu --manifest-path tests/hello-rustls/Cargo.toml
   Compiling cargo-zigbuild v0.6.7 (C:\Users\amitkatz\Desktop\cargo-zigbuild)
    Finished dev [unoptimized + debuginfo] target(s) in 34.12s
     Running `target\debug\cargo-zigbuild.exe zigbuild --target aarch64-unknown-linux-gnu --manifest-path tests/hello-rustls/Cargo.toml`
CommandEnvs { iter: [(EnvKey { os_string: "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER", utf16: [67, 65, 82, 71, 79, 95, 84, 65, 82, 71, 69, 84, 95, 65, 65, 82, 67, 72, 54, 52, 95, 85, 78, 75, 78, 79, 87, 78, 95, 76, 73, 78, 85, 88, 95, 71, 78, 85, 95, 76, 73, 78, 75, 69, 82] }, Some("C:\\Users\\amitkatz\\AppData\\Local\\cargo-zigbuild\\0.6.7\\zigcc-aarch64-unknown-linux-gnu.bat")), (EnvKey { os_string: "CC_AARCH64_UNKNOWN_LINUX_GNU", utf16: [67, 67, 95, 65, 65, 82, 67, 72, 54, 52, 95, 85, 78, 75, 78, 79, 87, 78, 95, 76, 73, 78, 85, 88, 95, 71, 78, 85] }, Some("C:\\Users\\amitkatz\\AppData\\Local\\cargo-zigbuild\\0.6.7\\zigcc-aarch64-unknown-linux-gnu.bat")), (EnvKey { os_string: "CXX_AARCH64_UNKNOWN_LINUX_GNU", utf16: [67, 88, 88, 95, 65, 65, 82, 67, 72, 54, 52, 95, 85, 78, 75, 78, 79, 87, 78, 95,
76, 73, 78, 85, 88, 95, 71, 78, 85] }, Some("C:\\Users\\amitkatz\\AppData\\Local\\cargo-zigbuild\\0.6.7\\zigcxx-aarch64-unknown-linux-gnu.bat"))] }

(DISCARDED THE VERBOSE PRINTING)

   Compiling hello-rustls v0.1.0 (C:\Users\amitkatz\Desktop\cargo-zigbuild\tests\hello-rustls)
    Finished dev [unoptimized + debuginfo] target(s) in 7m 18s

[messense]

it also looks for CC_{lower_cased_target} ? It's case sensitive ain't it?

Yes, it should be lower case.

[messense]

The nightly test failure is unrelated to this change: briansmith/ring#1469

[TheOnlyArtz]

The nightly test failure is unrelated to this change: briansmith/ring#1469

What can it be then?

[messense]

The nightly test failure is unrelated to this change: briansmith/ring#1469

What can it be then?

I don't know, opened rust-lang/rust#95267.

[messense]

Looks good to me, thanks!

[messense]

Released in v0.7.0: https://crates.io/crates/cargo-zigbuild/0.7.0