# Description: I was trying to build [cargo-whatfeatures](https://aur.archlinux.org/packages/cargo-whatfeatures) when the compilation failed with a link error. [link-failure.log](/uploads/e1061d69b82fd72374872ee0d61fba78/link-failure.log) Interestingly the error only happens when I use `makepkg` and not when I use `cargo` directly, which leads me to figure out that it's caused by flags in `makepkg.conf`. Doing a basic bisection, I was able to narrow it down to `LTOFLAGS="-flto=auto"`. After doing some research, I found [this issue](https://github.com/rust-lang/cargo/issues/2014) which gave a solution. I set `LTOFLAGS="-flto=auto -ffat-lto-objects"` in `makepkg.conf.d/rust.conf`, and build succeeded. From reading the description of `-ffat-lto-objects` in `man gcc`, (I'm no expert so I may very well be wrong on this) it seems like the reason for this is the linker used by `cargo` only supports normal linking, which necessitates this flag. Maybe specifying an alternate linker is the more idiomatic way to fix this; I'm not sure. Which is why I'm submitting an issue rather than a MR. # Additional info: * package version(s): 6.1.0-3 * config and/or log files: `makepkg.conf` and `makepkg.conf.d/rust.conf` unmodified * link to upstream bug report, if any: N/A This is not an isolated incident; I've also ran into the same issue with other Rust packages. The one I can recall right now is [ncspot-git](https://aur.archlinux.org/packages/ncspot-git). # Steps to reproduce: 1. With default `makepkg.conf` and `makepkg.conf.d/rust.conf`, build [cargo-whatfeatures](https://aur.archlinux.org/packages/cargo-whatfeatures). Notice the link failure. 2. Add `LTOFLAGS="-flto=auto -ffat-lto-objects` to `/etc/makepkg.conf.d/rust.conf`. 3. Run `makepkg` again. It should succeed.