--sysroot should be passed on to the linker

[Zoxc]

The linker needs to be passed the --sysroot option so it can find libraries when cross compiling.

I tried simply modifying rustc to pass the option on to the linker, but --sysroot is used during the bootstrap of rustc without an actual sysroot (i.e. there is only rust libraries, not C, so linking will fail).

[alexcrichton]

This seems like a use case for -C link-args as the Rust sysroot is very different from the C sysroot.

[Zoxc]

How is the Rust sysroot is very different from the C sysroot and why? I had plotted to use the same folder for both.

[alexcrichton]

The compiler currently has basically zero knowledge about the filesystem layout of the underlying C compiler, it just assumes the linker will find the right system libraries in the provided -L paths. In that sense there is no intention for the Rust sysroot to contain the C sysroot at all, so they're intended to be separate entities.

[Mark-Simulacrum]

Closing as per the above -- we don't intend to do this.