DragonFlyBSD

https://leaf.dragonflybsd.org/~tkusumi/diff/newfs_hammer2_split.patch

This patch splits newfs_hammer2(8) into newfs and mkfs part, similarly to newfs_msdos(8).

• The existing file newfs_hammer2.c now only does main() to handle options and call hammer2_mkfs().
• The new file mkfs_hammer2.c does actual newfs work in hammer2_mkfs().
• hammer2_mkfs() can be used by other programs.
• newfs_hammer2(8) behavior and features stay the same.

The intention of this change is HAMMER2 support for makefs(8) which needs hammer2_mkfs() functionality.
I'll commit this diff along with makefs(8) HAMMER2 support in a few days or so.

Note that unlike makefs(8) FAT (which has MAKEFS ifdefs in sys/vfs/msdos here and there), the upcoming makefs(8) HAMMER2 doesn't change a single line of code in sys/vfs/hammer2 or sbin/hammer2.