- 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

- Add support for IPC_64 extensions into shmctl(2), semctl(2) and msgctl(2);
- add wrappers for mmap2(2) and ftruncate64(2) system calls;
- don't spam console with printf's when VFAT_READDIR_BOTH ioctl(2) is invoked;
- add support for SOUND_MIXER_READ_STEREODEVS ioctl(2);
- make msgctl(IPC_STAT) and IPC_SET actually working by converting from
BSD msqid_ds to Linux and vice versa;
- properly return EINVAL if semget(2) is called with nsems being negative.

Reviewed by: marcel
Approved by: marcel
Tested with: LSB runtime test