Code:
# cd /tmp
# wget -r -nH --cut-dirs=5 -Rtar.xz ftp://ftp.osuosl.org/pub/slackware/slackware-current/source/d/doxygen
# cd doxygen
# wget http://ftp.stack.nl/pub/users/dimitri/doxygen-1.8.0.src.tar.gz
# ./*Build
# upgradepkg --install-new /tmp/doxygen-1.8.0-*t?z
# rm -rf /tmp/package-doxygen/ /tmp/doxygen-*/
does the task locally.