Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.Approved by: re (implicit)Sponsored by: The FreeBSD Foundation
mdoc: minor Bl improvements.
mdoc: order prologue macros consistently by Dd/Dt/OsAlthough groff_mdoc(7) gives another impression, this is the orderingmost widely used and also required by mdocml/mandoc.Reviewed by: ruApproved by: philip, ed (mentors)
MFP4: Add an implementation of the ELF(3) and GELF(3) API set.Bump __FreeBSD_version.Reviewed by: jb