graphics/libdrm: Update to 2.4.99
Update graphics/libdrm to 2.4.99
Changelog:
https://lists.x.org/archives/xorg-announce/2019-July/003001.html
PR: 239205
Reported by: Shankar Giri
Obtained from: FreeBSD Graphics Team development repo
https://github.com/FreeBSDDesktop/freebsd-ports/tree/feature/xorglibs
Sponsored by: B3 Init