Makefile: add support for $LIBDIR

Enable make to specify ${PREFIX}${LIBDIR} to install library
files to e.g. /usr/lib or /usr/lib64 depending on the arch.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Makefile: break too long lines to be readable

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Makefile: fix invalid variable in uninstall

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Merge pull request #3 from dalgaaf/wip-da-build-fixes

Fixes for build/make