if [ $$? -ne 0 ]; then \
echo failed to run doxygen on our configuration file.; \
echo perhaps doxygen is not properly installed?; \
echo these are the ubuntu install steps:; \
echo sudo apt install doxygen graphviz; \
if [ $$? -ne 0 ]; then \
echo failed to run doxygen on our configuration file.; \
echo perhaps doxygen is not properly installed?; \
echo these are the ubuntu install steps:; \
echo sudo apt install doxygen graphviz; \