Build configure fails due to missing Cargo

[itarato]

I've noticed the Cargo documentation seems to require Cargo already installed on the system. Even so that the build instructions have a no-cargo scenario, if I run ./configure it fails with the following error:

configure: processing ./configure args
configure: 
configure: CFG_PREFIX           := /usr/local 
configure: CFG_LOCAL_RUST_ROOT  :=  
configure: CFG_CARGO            := cargo 
configure: CFG_RUSTC            := rustc 
configure: CFG_RUSTDOC          := rustdoc 
configure: CFG_CARGO            :=  
configure: error: needed, but unable to find any of: CFG_CARGO cargo

In my case I compiled Rust from source, which doesn't have Cargo included anymore. Also as far as I know it is a bad practice to have a pre-existing Rust install (such as via rustup) when compiling Rust and Cargo. In any case, I couldn't figure out from the makefile or the docs if I really need to install Cargo before I build the project.
For clarity - my intention is to build Cargo (and Rust) from source.
What do you recommend?

[alexcrichton]

Indeed yeah Cargo is required to compile Cargo. In future Rust releases we'll have --enable-extended which will compile Cargo as well as Rust.

In general though having an existing Rust install when compiling from source should work just fine, no need to avoid it.

[itarato]

Thanks @alexcrichton

[0joshuaolson1]

In future Rust releases we'll have --enable-extended

@alexcrichton is there an issue for this?

[alexcrichton]

@0joshuaolson1 it's currently present on the master branch of rust-lang/rust

[0joshuaolson1]

That started with this commit, right? I see --enable-extented in beta and stable too.

Can I use the cargo build outside of Docker if my machine is the right arch?

[alexcrichton]

Sorry I'm not really sure what you're asking? How does this relate to this issue?

[0joshuaolson1]

--enable-extended which will compile Cargo as well as Rust.

I was interested in learning how to use this to compile Cargo without Cargo.

[alexcrichton]

Unfortunately that's not really supported right now, if you're looking to port Cargo to a new platform you'll need to do so through cross-compilation.

[0joshuaolson1]

Thanks.