Custom rustflag for specific binary only?

[tyamadajp]

I have a project that builds multiple binaries using separate sources in src/ folder.

In this configuration, I want to pass custom rustflag to build one of these binaries using custom linker script (-Tlink.x, along with custom build.rs). How can I accomplish this?

I tried various ways to set rustflags, but all broke build of other binaries or depending libraries.

1. Running cargo with RUSTFLAGS="..." cargo build ... caused other builds to fail, as all rustc invocation got this arg passed.
2. Setting rustflags=... in [build] or [target.triplet] section of .cargo/config also failed, as rustflags applied to all other compilation/linking as well.

While it does not work, what I essentially want is to write following:

in .cargo/config

[build.foobinary]
rustflags = ...

or

in Cargo.toml

[[bin]]
name = foobinary
rustflags = ...

Is there any way to do something equivalent?

[tyamadajp]

I found a resolution myself. Embedding custom linker arg in the source solved it:

#![feature(link_args)]
...
#[link_args="-Tlink.x"]
#[link_args="-Wl,--no-relax"]
extern "C" {
...declarations that relies on custom linker script...
}

did the trick, along with custom build.rs to copy link.x into linker script search path.