ci: build linux-aarch64 on native ARM runner instead of cross

.github/workflows/rust-multiplatform.yml

@@ -15,7 +15,6 @@ on:
       - 'vendor/skia-safe-op/**'
       - 'rust-toolchain.toml'
       - 'deny.toml'
-      - 'Cross.toml'
       - '.github/workflows/rust-multiplatform.yml'
   pull_request:
     paths:
@@ -24,7 +23,6 @@ on:
       - 'crates/**'
       - 'vendor/jian/**'
       - 'vendor/skia-safe-op/**'
-      - 'Cross.toml'
       - '.github/workflows/rust-multiplatform.yml'
   workflow_dispatch:
 
@@ -52,10 +50,14 @@ jobs:
             runner: ubuntu-latest
             target: x86_64-unknown-linux-gnu
             cross: false
+          # Native ARM64 hosted runner — no `cross`. The cross 0.2.x aarch64
+          # image (Ubuntu 16.04 / GCC 5 / FreeType 2.6) is too old to link the
+          # modern skia that skia-bindings builds (missing COLR/variable-font
+          # FreeType symbols + libstdc++ ABI mismatch).
           - label: linux-aarch64
-            runner: ubuntu-latest
+            runner: ubuntu-24.04-arm
             target: aarch64-unknown-linux-gnu
-            cross: true
+            cross: false
           - label: windows-x86_64
             runner: windows-latest
             target: x86_64-pc-windows-msvc

Cross.toml

@@ -1,11 +0,0 @@
-# Cross-compilation config for `cross` (used by the linux-aarch64 CI job).
-#
-# The aarch64 cross build links the `openpencil-desktop` binary, which pulls
-# system freetype + fontconfig at link time (via skia-bindings and
-# sctk-adwaita). The stock cross image only ships host-arch libs, so the
-# target-arch dev packages must be installed into the container before build.
-[target.aarch64-unknown-linux-gnu]
-pre-build = [
-  "dpkg --add-architecture $CROSS_DEB_ARCH",
-  "apt-get update && apt-get --assume-yes install libfreetype6-dev:$CROSS_DEB_ARCH libfontconfig1-dev:$CROSS_DEB_ARCH",
-]