From 940b78a7c08f2eab0d3be37131623412afd6aee7 Mon Sep 17 00:00:00 2001
From: Jolyon Suthers <201621+fenrick@users.noreply.github.com>
Date: Wed, 9 Sep 2026 23:51:18 +1000
Subject: [PATCH] fix: install the ARM64 C library so Linux ARM64 links

v1.1.0 published no Linux ARM64 assets. Both jobs failed to link with
"cannot find crti.o" and "cannot find -lc": gcc-aarch64-linux-gnu only
*recommends* libc6-dev-arm64-cross, and the install used
--no-install-recommends, so the cross compiler arrived without a target C
library. The library is now named explicitly alongside it.

CI could not have caught this. It ran `cargo check`, which does not link,
so a missing link-time dependency was invisible until a release ran. The
targets job now runs `cargo build --release` for all five targets, with
the cross toolchain where one is needed, so a link failure surfaces on the
pull request that causes it.

v1.1.0 keeps its other twelve assets: fail-fast was already disabled on
the packaging job, so the failure cost only the two new architectures.
---
 .github/workflows/ci.yml      | 27 ++++++++++++++++++++-------
 .github/workflows/release.yml | 14 ++++++++++----
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d921982..a3ad604 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -37,17 +37,26 @@ jobs:
       - name: Tests
         run: cargo test --all-features
 
-  # The release workflow cross-compiles four targets. Proving they still
-  # compile here means a release never fails on a platform nobody built.
+  # The release workflow builds five targets, two of them cross-compiled.
+  # Building — not merely checking — is the point: `cargo check` does not link,
+  # and a missing cross C library is a link error. v1.1.0 shipped without its
+  # Linux ARM64 assets for exactly that reason.
   targets:
-    name: Compiles for ${{ matrix.target }}
+    name: Builds for ${{ matrix.target }}
     runs-on: ${{ matrix.os }}
+    # Only consulted when building the matching target.
+    env:
+      CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER: aarch64-linux-gnu-gcc
     strategy:
       fail-fast: false
       matrix:
         include:
           - { target: x86_64-unknown-linux-gnu, os: ubuntu-latest }
-          - { target: aarch64-unknown-linux-gnu, os: ubuntu-latest }
+          - {
+              target: aarch64-unknown-linux-gnu,
+              os: ubuntu-latest,
+              apt: "gcc-aarch64-linux-gnu libc6-dev-arm64-cross",
+            }
           - { target: aarch64-apple-darwin, os: macos-latest }
           - { target: x86_64-pc-windows-msvc, os: windows-latest }
           - { target: aarch64-pc-windows-msvc, os: windows-latest }
@@ -58,13 +67,17 @@ jobs:
         with:
           targets: ${{ matrix.target }}
 
+      - name: Install cross toolchain
+        if: matrix.apt != ''
+        run: |
+          sudo apt-get update
+          sudo apt-get install --yes --no-install-recommends ${{ matrix.apt }}
+
       - uses: Swatinem/rust-cache@v2
         with:
           key: ${{ matrix.target }}
 
-      # `check` does not link, so no cross-linker is needed here. Linking is
-      # exercised by the release workflow.
-      - run: cargo check --all-targets --target ${{ matrix.target }}
+      - run: cargo build --release --target ${{ matrix.target }}
 
   # Guard the promise the README makes: an ordinary export carries no personal
   # data, and no real document is ever committed.
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 942fd82..ee005e9 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -51,7 +51,7 @@ jobs:
       matrix:
         include:
           - { target: x86_64-unknown-linux-gnu, os: ubuntu-latest }
-          - { target: aarch64-unknown-linux-gnu, os: ubuntu-latest, apt: gcc-aarch64-linux-gnu }
+          - { target: aarch64-unknown-linux-gnu, os: ubuntu-latest, apt: "gcc-aarch64-linux-gnu libc6-dev-arm64-cross" }
           - { target: aarch64-apple-darwin, os: macos-latest }
           - { target: x86_64-pc-windows-msvc, os: windows-latest }
           - { target: aarch64-pc-windows-msvc, os: windows-latest }
@@ -64,7 +64,10 @@ jobs:
         with:
           targets: ${{ matrix.target }}
 
-      - name: Install cross-linker
+      # The cross compiler only *recommends* the target C library, so the
+      # library has to be named explicitly alongside it: without it the linker
+      # reports "cannot find crti.o" and "cannot find -lc".
+      - name: Install cross toolchain
         if: matrix.apt != ''
         run: |
           sudo apt-get update
@@ -113,7 +116,7 @@ jobs:
       matrix:
         include:
           - { target: x86_64-unknown-linux-gnu, arch: amd64 }
-          - { target: aarch64-unknown-linux-gnu, arch: arm64, apt: gcc-aarch64-linux-gnu }
+          - { target: aarch64-unknown-linux-gnu, arch: arm64, apt: "gcc-aarch64-linux-gnu libc6-dev-arm64-cross" }
     steps:
       - uses: actions/checkout@v7
         with:
@@ -123,7 +126,10 @@ jobs:
         with:
           targets: ${{ matrix.target }}
 
-      - name: Install cross-linker
+      # The cross compiler only *recommends* the target C library, so the
+      # library has to be named explicitly alongside it: without it the linker
+      # reports "cannot find crti.o" and "cannot find -lc".
+      - name: Install cross toolchain
         if: matrix.apt != ''
         run: |
           sudo apt-get update