add BUILD_ARCH in drone.yml

Dockerfile

@@ -30,14 +30,17 @@ RUN printf '#-------------------------------------------------------------------
 \n' > /etc/apt/sources.list
 
 # Build deps and clean up
+# Crossbuilding: https://wiki.debian.org/CrossCompiling#Building_with_dpkg-buildpackage
 ARG BUILD_DEPS
+ARG BUILD_ARCH
 RUN export DEBIAN_FRONTEND=noninteractive && \
-    dpkg --add-architecture armhf && \
+    for ARCH in ${BUILD_ARCH} ; do dpkg --add-architecture ${ARCH} ; done && \
     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 apt-utils && \
     apt-get -qy -o Dpkg::Use-Pty=0 install --no-install-recommends ${BUILD_DEPS} \
-        build-essential crossbuild-essential-armhf debhelper ca-certificates curl git iproute2 wget nano && \
+        build-essential debhelper ca-certificates curl git iproute2 wget nano && \
+    for ARCH in ${BUILD_ARCH} ; do apt-get -qy -o Dpkg::Use-Pty=0 install --no-install-recommends crossbuild-essential-${ARCH} ; done && \
     apt-get clean && rm -rf /var/lib/apt/lists/*
 
 # Default command

drone.yml

@@ -41,6 +41,7 @@ steps:
     build_args: # custom args for docker build, e.g. additional BUILD_DEPS etc.
       - DEB_RELEASE=stretch
       - BUILD_DEPS=libhidapi-dev libssl-dev zip
+      - BUILD_ARCH=i386 armhf # amd64 arm64 armel armhf i386 mips mips64el mipsel powerpc ppc64el s390x
 
 
 - name: build