fix: install correct mc binary for arm64

containers/jug/dev.Dockerfile

@@ -188,9 +188,18 @@ COPY profile.d/z11_jug_env.sh /etc/profile.d
 COPY singularity.d /.singularity.d
 
 ## Add minio client into /usr/local/bin
-## FIXME: This should download .../linux-arm64/mc for arm64.
-ADD https://dl.min.io/client/mc/release/linux-amd64/mc /usr/local/bin
-RUN chmod a+x /usr/local/bin/mc
+ADD https://dl.min.io/client/mc/release/linux-amd64/mc /usr/local/bin/mc-amd64
+ADD https://dl.min.io/client/mc/release/linux-arm64/mc /usr/local/bin/mc-arm64
+RUN declare -A target=(                                                 \
+      ["linux/amd64"]="amd64"                                           \
+      ["linux/arm64"]="arm64"                                           \
+    )                                                                   \
+ && mv /usr/local/bin/mc-${target[${TARGETPLATFORM}]} /usr/local/bin/mc \
+ && chmod a+x /usr/local/bin/mc                                         \
+ && unset target[${TARGETPLATFORM}]                                     \
+ && for t in ${target[*]} ; do                                          \
+      rm /usr/local/bin/mc-${t} ;                                       \
+    done
 
 ## ========================================================================================
 ## STAGE 3