- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Remove unneeded reference to link.h (sys/link_elf.h).

MFC after: 2 weeks

Make our ELF64 type definitions match standards. In particular this
means:
o Remove Elf64_Quarter,
o Redefine Elf64_Half to be 16-bit,
o Redefine Elf64_Word to be 32-bit,
o Add Elf64_Xword and Elf64_Sxword for 64-bit entities,
o Use Elf_Size in MI code to abstract the difference between
Elf32_Word and Elf64_Word.
o Add Elf_Ssize as the signed counterpart of Elf_Size.

MFC after: 2 weeks

Explicitly pass in the relocation base and data offset into ef_reloc()
rather than relying on a trick that happens to work for the current
relocation schemes. Also add some comments and improve variable
naming.

Add MD relocation support for amd64 and i386 platforms. The no-op
relocation is not sufficient for ELF relocatable object format
modules, since accessing the module metadata involves following
pointers between different ELF sections.

This allows kldxref to correctly build linker.hints on the amd64
platform.