added support for armhf

Dockerfile

@@ -1,19 +1,19 @@
-FROM tomcat:7-jre8
+FROM library/tomcat:7-jre8
 
-ENV GUAC_VER=0.9.13-incubating \
-  GUACAMOLE_HOME=/app/guacamole
-
-ENV PG_MAJOR=9.6 \
+ENV ARCH=amd64 \
+  GUAC_VER=0.9.13-incubating \
+  GUACAMOLE_HOME=/app/guacamole \
+  PG_MAJOR=9.6 \
   PGDATA=/config/postgres \
   POSTGRES_USER=guacamole \
   POSTGRES_DB=guacamole_db
 
 # Apply the s6-overlay
 
-RUN curl -SLO "https://github.com/just-containers/s6-overlay/releases/download/v1.20.0.0/s6-overlay-amd64.tar.gz" \
-  && tar -xzf s6-overlay-amd64.tar.gz -C / \
-  && tar -xzf s6-overlay-amd64.tar.gz -C /usr ./bin \
-  && rm -rf s6-overlay-amd64.tar.gz \
+RUN curl -SLO "https://github.com/just-containers/s6-overlay/releases/download/v1.20.0.0/s6-overlay-${ARCH}.tar.gz" \
+  && tar -xzf s6-overlay-${ARCH}.tar.gz -C / \
+  && tar -xzf s6-overlay-${ARCH}.tar.gz -C /usr ./bin \
+  && rm -rf s6-overlay-${ARCH}.tar.gz \
   && mkdir -p ${GUACAMOLE_HOME} \
     ${GUACAMOLE_HOME}/lib \
     ${GUACAMOLE_HOME}/extensions
@@ -31,14 +31,15 @@ RUN apt-get update && apt-get install -y \
   && rm -rf /var/lib/apt/lists/*
 
 # Link FreeRDP to where guac expects it to be
-RUN ln -s /usr/local/lib/freerdp /usr/lib/x86_64-linux-gnu/freerdp
+RUN [ "$ARCH" = "armhf" ] && ln -s /usr/local/lib/freerdp /usr/lib/arm-linux-gnueabihf/freerdp || exit 0
+RUN [ "$ARCH" = "amd64" ] && ln -s /usr/local/lib/freerdp /usr/lib/x86_64-linux-gnu/freerdp || exit 0
 
 # Install guacamole-server
 RUN curl -SLO "https://sourceforge.net/projects/guacamole/files/current/source/guacamole-server-${GUAC_VER}.tar.gz" \
   && tar -xzf guacamole-server-${GUAC_VER}.tar.gz \
   && cd guacamole-server-${GUAC_VER} \
   && ./configure \
-  && make \
+  && make -j$(getconf _NPROCESSORS_ONLN) \
   && make install \
   && cd .. \
   && rm -rf guacamole-server-${GUAC_VER}.tar.gz guacamole-server-${GUAC_VER} \