Simplify build process with cross

Refactors actions builds to use cross for cross-compilation instead of
manually setting up the infrastructure which is extremely fragile, and
makes adding new archs hard.

This also simplifies the Dockerfile a bit, making it plug-n-play with
any rust platform that has first-party host tools.

.github/workflows/rust.yml

@@ -4,7 +4,6 @@ on: [ push, pull_request ]
 
 env:
   CARGO_TERM_COLOR: always
-  CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER: aarch64-linux-gnu-gcc
 
 jobs:
   build:
@@ -13,44 +12,47 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          # x86_64
           - target: 'x86_64-pc-windows-msvc'
             os: windows
           - target: 'x86_64-unknown-linux-gnu'
             os: ubuntu
           - target: 'x86_64-unknown-linux-musl'
             os: ubuntu
+          # aarch64 (armv8)
           - target: 'aarch64-unknown-linux-gnu'
             os: ubuntu
           - target: 'aarch64-unknown-linux-musl'
             os: ubuntu
+          # armv7
+          - target: 'armv7-unknown-linux-gnueabihf'
+            os: ubuntu
+          - target: 'armv7-unknown-linux-musleabihf'
+            os: ubuntu
+          # armv6
+          - target: 'arm-unknown-linux-gnueabihf'
+            os: ubuntu
+          - target: 'arm-unknown-linux-musleabihf'
+            os: ubuntu
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v4
 
-      - name: Install musl Dependencies
-        if: contains(matrix.target, 'musl')
-        run: sudo apt-get update && sudo apt-get install musl-tools
-
-      - name: Install aarch64 Dependencies
-        if: contains(matrix.target, 'aarch64')
-        run: sudo apt-get update && sudo apt-get install gcc-aarch64-linux-gnu
-
-      - name: Setup aarch64 musl compiler
-        if: contains(matrix.target, 'aarch64') && contains(matrix.target, 'musl')
-        run: |
-          wget https://musl.cc/aarch64-linux-musl-cross.tgz
-          tar -xvzf aarch64-linux-musl-cross.tgz
-          echo "CC=$(pwd)/aarch64-linux-musl-cross/bin/aarch64-linux-musl-gcc" >> "$GITHUB_ENV"
-
-      - name: Install Target
-        run: rustup target add ${{ matrix.target }}
+      - name: Install Cross
+        run: cargo install --git https://github.com/cross-rs/cross cross
 
       - name: Setup Cache
         uses: Swatinem/rust-cache@v2
 
-      - name: Build
+      # cross doesn't support msvc toolchains out-of-the-box (https://github.com/cross-rs/cross-toolchains)
+      - name: Build (Windows)
+        if: matrix.os == 'windows'
         run: cargo build --release --target=${{ matrix.target }}
 
+      - name: Build (Linux)
+        if: matrix.os == 'ubuntu'
+        run: cross build --release --target=${{ matrix.target }}
+
       - name: Upload Artifact
         uses: actions/upload-artifact@v4
         with:

Dockerfile

@@ -3,19 +3,14 @@
 ####################################################################################################
 FROM rust:alpine AS builder
 
-RUN apk add --no-cache musl-dev gcc # GCC needed for aarch64 builds
+RUN apk add --no-cache musl-dev
 
 WORKDIR /intellectual
 
 COPY . .
 
 # Figure out what arch we're on
-RUN BASE_TARGET=-unknown-linux-musl; \
-    case "$(uname -m)" in \
-        x86_64) TARGET=x86_64$BASE_TARGET ;; \
-        aarch64) TARGET=aarch64$BASE_TARGET ;; \
-        *) echo "Unsupported architecture"; exit 1 ;; \
-    esac; \
+RUN TARGET=$(uname -m)-unknown-linux-musl; \
 # Set environment variables so the build has git info
     export $(cat .env | xargs); \
 # Build the binary