Bug 1779386 - Build geckodriver for aarch64 on Linux. r=whimboo

Differential Revision: https://phabricator.services.mozilla.com/D156646

taskcluster/ci/toolchain/geckodriver.yml

@@ -50,6 +50,19 @@ linux64-geckodriver:
         toolchain:
             - linux64-rust-static
 
+linux64-aarch64-geckodriver:
+    treeherder:
+        symbol: TL(gd)
+        platform: linux64-aarch64/opt
+    run:
+        arguments: ['aarch64-unknown-linux-musl']
+    attributes:
+        build_platform: linux64-aarch64-geckodriver
+    fetches:
+        toolchain:
+            - linux64-clang-toolchain
+            - linux64-rust-static
+
 macosx64-geckodriver:
     treeherder:
         symbol: TM(gd)

taskcluster/ci/toolchain/rust.yml

@@ -97,6 +97,7 @@ linux64-rust-static-1.63:
         arguments: [
             '--channel', '1.63.0',
             '--host', 'x86_64-unknown-linux-gnu',
+            '--target', 'aarch64-unknown-linux-musl',
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-unknown-linux-musl',
             '--target', 'i686-unknown-linux-gnu',

taskcluster/ci/upload-symbols/kind.yml

@@ -23,6 +23,7 @@ not-for-build-platforms:
     - win64-asan-reporter-shippable/opt
     - linux-geckodriver/opt
     - linux64-geckodriver/opt
+    - linux64-aarch64-geckodriver/opt
     - macosx64-geckodriver/opt
     - macosx64-aarch64-geckodriver/opt
     - win32-geckodriver/opt

taskcluster/scripts/misc/build-geckodriver.sh

@@ -39,6 +39,9 @@ case "$TARGET" in
       export MACOSX_DEPLOYMENT_TARGET=10.12
   fi
   ;;
+aarch64-unknown-linux-musl)
+  export RUSTFLAGS="-C linker=$MOZ_FETCHES_DIR/clang/bin/clang -C link-arg=--target=$TARGET -C link-arg=-fuse-ld=lld"
+  ;;
 esac
 
 export PATH="$MOZ_FETCHES_DIR/rustc/bin:$PATH"