or just give and install rustc already

docker/4_run/Dockerfile

@@ -11,6 +11,7 @@ RUN set -ex; \
         libjpeg8 \
         libtiff5 \
         ffmpeg \
+        rustc \
         rsyslog logrotate \
         nano vim-tiny curl; \
     rm -rf /var/lib/apt/lists/*