use cpu core routine

Dockerfile

@@ -71,7 +71,21 @@ RUN \
 	--without-x \
 	--with-tiff \
 	--with-xml && \
- make && \
+# attempt to set number of cores available for make to use
+ set -ex && \
+ CPU_CORES=$( < /proc/cpuinfo grep -c processor ) || echo "failed cpu look up" && \
+ if echo $CPU_CORES | grep -E  -q '^[0-9]+$'; then \
+	: ;\
+ if [ "$CPU_CORES" -gt 7 ]; then \
+	CPU_CORES=$(( CPU_CORES  - 3 )); \
+ elif [ "$CPU_CORES" -gt 5 ]; then \
+	CPU_CORES=$(( CPU_CORES  - 2 )); \
+ elif [ "$CPU_CORES" -gt 3 ]; then \
+	CPU_CORES=$(( CPU_CORES  - 1 )); fi \
+ else CPU_CORES="1"; fi && \
+
+ make -j $CPU_CORES && \
+ set +ex && \
  make install && \
  find / -name '.packlist' -o -name 'perllocal.pod' \
 	-o -name '*.bs' -delete && \

README.md

@@ -98,5 +98,6 @@ To reverse proxy with our Letsencrypt docker container use the following locatio
 
 ## Versions
 
++ **27.11.17:** Use cpu core counting routine to speed up build time.
 + **24.07.17:** Curl version for imagemagick.
 + **17.07.17:** Initial release.