Detect arch in portable build

.github/workflows/publish-docker-and-wsl.yaml

@@ -39,7 +39,7 @@ jobs:
       uses: docker/build-push-action@v2
       with:
         file: ./portable.Dockerfile
-        platforms: linux/amd64
+        platforms: linux/amd64,linux/arm64
         push: true
         tags: |
           ${{ steps.docker_meta.outputs.tags }}

docker/g++

@@ -9,4 +9,9 @@ do
     fi
 done
 
-/usr/bin/g++_real -march=nehalem "${args[@]}"
+ARCH=nehalem
+if [[ $(uname -m) == "aarch64" ]];
+    ARCH=armv8-a
+fi
+
+/usr/bin/g++_real -march=$ARCH "${args[@]}"

docker/gcc

@@ -9,4 +9,9 @@ do
     fi
 done
 
-/usr/bin/gcc_real -march=nehalem "${args[@]}"
+ARCH=nehalem
+if [[ $(uname -m) == "aarch64" ]];
+    ARCH=armv8-a
+fi
+
+/usr/bin/gcc_real -march=$ARCH "${args[@]}"