attempt 3

scripts/Dockerfile.build

@@ -0,0 +1,25 @@
+# Build environment for qroissant.
+#
+# Base: ghcr.io/rust-cross/cargo-xwin — Debian 13, ships with cargo-xwin,
+# llvm-dlltool, and the x86_64-pc-windows-msvc rustup target preinstalled.
+# We layer on nightly Rust (project uses #![feature(portable_simd)]),
+# lld (so cargo-xwin can invoke lld-link), and maturin.
+FROM ghcr.io/rust-cross/cargo-xwin:latest
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get update \
+ && apt-get install -y --no-install-recommends lld python3-pip python3-venv \
+ && rm -rf /var/lib/apt/lists/* \
+ && ln -sf /usr/bin/lld /usr/bin/lld-link \
+ && ln -sf /usr/bin/clang /usr/bin/clang-cl
+
+RUN rustup toolchain install nightly --profile minimal \
+        --component rustfmt --component clippy --component rust-src \
+        --component llvm-tools-preview \
+ && rustup target add --toolchain nightly x86_64-pc-windows-msvc \
+ && rustup default nightly
+
+RUN pip3 install --no-cache-dir --break-system-packages 'maturin>=1.8,<2.0'
+
+ENV PATH="/usr/local/cargo/bin:${PATH}"