This useflag enables capability of dynamic loading interfaces/modules and plugins for DirectFB. As we build it dynamically, having this flag disabled makes DirectFB completely unusable with errors like 'no system found' even when proper libs are in right place. Details can be viewed at lib/direct/interface.c in DirectFB sources
+ 31 Jul 2014; Sergey Popov <pinkbyte@gentoo.org> DirectFB-1.6.3-r1.ebuild, + DirectFB-1.7.1.ebuild: + Enable USE="dynload" by default, wrt bug #517184