Created attachment 434298 [details] virtualbox-5.0.20.diff Part of the logging facility is not exploitable until virtualbox is built in debug mode, for this reason the VBOX_LOG, VBOX_LOG_DEST and VBOX_LOG_FLAGS env vars are ignored. I have modified the ebuild, patch attached, to change the building mode to support the env vars as described https://www.virtualbox.org/wiki/VBoxLogging, probably it might be useful to put a notice to the user in pkg_postint()
commit 4ee2afe9963781b4654b4c1c3f3148a287023c03 Author: Lars Wendler <polynomial-c@gentoo.org> Date: Sun May 15 21:36:22 2016 app-emulation/virtualbox: Added debug USE flag (bug #583052). Package-Manager: portage-2.2.28 Signed-off-by: Lars Wendler <polynomial-c@gentoo.org> Added the flag without revbump and without elog message in pkg_postinst.