Fix: broken nightly builds

In recent versions of the nightly / beta compilers, the use of linkme
causes linker errors. (dtolnay/linkme#94) This
is due to the new linker set as default in these versions.

Add linker flags to nightly builds to revert to the old linker
behaviour.

See:

- dtolnay/linkme#88
- https://blog.rust-lang.org/2024/05/17/enabling-rust-lld-on-linux.html

Signed-off-by: Niklas Dewally <niklas@dewally.com>

.github/workflows/code-coverage-main.yml

@@ -27,6 +27,10 @@ jobs:
       - name: Install rust ${{ env.rust_release }}
         run: rustup update ${{ env.rust_release }} && rustup default ${{ env.rust_release }}
 
+      - name: Disable rust-lld (to fix linkme)
+        run: echo RUSTFLAGS=${RUSTFLAGS}\ -Zlinker-features=-lld >> $GITHUB_ENV
+        if: matrix.rust == 'nightly'
+
       - uses: ./.github/actions/install-conjure
         with: 
           os_arch: linux

.github/workflows/code-coverage.yml

@@ -40,6 +40,10 @@ jobs:
 
       - name: Install rust ${{ env.rust_release }}
         run: rustup update ${{ env.rust_release }} && rustup default ${{ env.rust_release }}
+
+      - name: Disable rust-lld (to fix linkme)
+        run: echo RUSTFLAGS=${RUSTFLAGS}\ -Zlinker-features=-lld >> $GITHUB_ENV
+        if: matrix.rust == 'nightly'
 
       - uses: ./.github/actions/install-conjure
         with: 

.github/workflows/test.yml

@@ -54,6 +54,10 @@ jobs:
       - name: Run sccache-cache
         uses: mozilla-actions/sccache-action@v0.0.3
 
+      - name: Disable rust-lld (to fix linkme)
+        run: echo RUSTFLAGS=${RUSTFLAGS}\ -Zlinker-features=-lld >> $GITHUB_ENV
+        if: matrix.rust == 'nightly'
+
       - run: rustup update ${{ matrix.rust_release }} && rustup default ${{ matrix.rust_release }}
 
       - run: cargo build -vv --workspace

readme.md

@@ -13,6 +13,20 @@ This repository hosts the following projects:
 This project is being produced by staff and students of University of St
 Andrews, and is licenced under the [MPL 2.0](./LICENCE).
 
+## Rust Nightly Support
+
+The following compiler flags are required for Conjure-Oxide to work with
+Nightly Rust:
+
+```sh
+export RUSTFLAGS="-Zlinker-features=-lld" 
+cargo build <...>
+```
+
+This is because of current incompatibilities with linkme and the new default
+linker ([link](https://github.com/dtolnay/linkme/issues/94)).
+
+
 ## Documentation
 
 API documentation can be found [here](https://conjure-cp.github.io/conjure-oxide/docs/).