libdirectfb* is copied to target, but when the package builds it also builds
libdirect* and libfusion*, which libdirectfb will call upon, but they are not
copied along with libdirectfb.
Building DirectFB compiles fine and installs fine, but when running on the
target the libraries look for DirectFB modules within a path that was defined
as $(PREFIX) during the build. Under buildroot PREFIX is set to
$(STAGING_DIR)/usr, which obviously doesn't exist on the target so it dies.
Instead, it should be built such that PREFIX=/usr then have prefix &
exec_prefix set to $(STAGING_DIR)/usr when it's time to install.
