add armhf arch

Dockerfile

 # Define builder target
-FROM debian:stable-slim as builder
+ARG DEB_RELEASE
+FROM debian:${DEB_RELEASE}-slim as builder
 
 # Environment PATH HOME HOSTNAME
 # ENV PATH /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
 # ENV HOME /
 
+ARG DEB_RELEASE
+RUN printf '#------------------------------------------------------------------------------#\
+\n#                   OFFICIAL DEBIAN REPOS\
+\n#------------------------------------------------------------------------------#\
+\n# apt install curl wget apt-transport-https dirmngr\
+\n\
+\n###### Debian Main Repos\
+\ndeb     http://deb.debian.org/debian/		'${DEB_RELEASE}'			main # contrib non-free\
+\ndeb-src http://deb.debian.org/debian/		'${DEB_RELEASE}'			main # contrib non-free\
+\n\
+\n# stretch-updates, previously known as "volatile"\
+\ndeb     http://deb.debian.org/debian/		'${DEB_RELEASE}'-updates		main # contrib non-free\
+\ndeb-src http://deb.debian.org/debian/		'${DEB_RELEASE}'-updates		main # contrib non-free\
+\n\
+\ndeb     http://deb.debian.org/debian-security	'${DEB_RELEASE}'/updates		main\
+\ndeb-src http://deb.debian.org/debian-security	'${DEB_RELEASE}'/updates		main\
+\n\
+\n# stretch-backports, previously on backports.debian.org\n\
+\ndeb     http://ftp.debian.org/debian		'${DEB_RELEASE}'-backports	main\
+\ndeb-src http://ftp.debian.org/debian		'${DEB_RELEASE}'-backports	main\
+' >> /etc/apt/sources.list
+
+RUN cat /etc/apt/sources.list
+
+
 # Build deps and clean up
 ARG BUILD_DEPS
 RUN export DEBIAN_FRONTEND=noninteractive && \
+    dpkg --add-architecture armhf && \
     apt-get -q  update && \
     apt-get -qy -o Dpkg::Use-Pty=0 upgrade && \
     apt-get -qy -o Dpkg::Use-Pty=0 install --no-install-recommends ${BUILD_DEPS} \
-        build-essential ca-certificates curl git iproute2 wget && \
+        build-essential crossbuild-essential-armhf debhelper ca-certificates curl git iproute2 wget nano && \
     apt-get clean && rm -rf /var/lib/apt/lists/*
 
 # Default command
 CMD ["bash"]
+