maybe it works with those changes now?

.github/workflows/rust.yml

@@ -54,3 +54,36 @@ jobs:
 
       - name: build example -- glibc size-optimized
         run: cd example && make clean && make TARGET=aarch64-unknown-linux-gnu PROFILE=size-optimized CARGO="rustup run nightly cargo" LTO=1
+
+  # this _should_ have been -stable, but there is a bug when running in the container ("Invalid cross-device link")
+  build-musl-beta:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Update repos
+        run: sudo apt-get update -qq
+      - name: Install toolchain
+        run: sudo apt-get install -qy liblzma-dev gcc make pkgconf musl-dev musl-tools rustup
+      - name: install rust target
+        run: rustup default beta && rustup target add aarch64-unknown-linux-musl && rustup component add rust-src && rustup update
+
+      - name: build example -- musl release
+        run: cd example && make clean && make TARGET=aarch64-unknown-linux-musl PROFILE=release MUSL=1 CARGO="rustup run beta cargo"
+      - name: build example -- musl debug
+        run: cd example && make clean && make TARGET=aarch64-unknown-linux-musl PROFILE=debug MUSL=1 CARGO="rustup run beta cargo"
+
+  build-size-musl-unstable:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Update repos
+        run: sudo apt-get update -qq
+      - name: Install toolchain
+        run: sudo apt-get install -qy liblzma-dev gcc make pkgconf musl-dev musl-tools rustup
+      - name: install rust targets
+        run: rustup toolchain install nightly -t aarch64-unknown-linux-musl -c rust-src --no-self-update
+
+      - name: build example -- musl size-optimized
+        run: cd example && make clean && make TARGET=aarch64-unknown-linux-musl PROFILE=size-optimized MUSL=1 LTO=1 CARGO="rustup run nightly cargo"