tyler writes:

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.