Log Message:
Update to 2.10.0.0. From the changelog:

- New openc_* functions.
- New function: ipc_bind_reuse_lock(), taking a lock before
  unconditionally deleting the socket.
- ipc_bind_reuse() rewritten to use ipc_bind_reuse_lock(),
  so it does the right thing instead of clobbering sockets.
- Complete revamping of the pathexec functions, see exec.h.
- Revamping of the locking functions.
- Use of standard O_NONBLOCK and O_CLOEXEC instead of adhoc
  DJBUNIX_FLAG_NB and DJBUNIX_FLAG_COE.
- Better header separation; webipc.h removed (stuff moved to
  socket.h)
- New function: mkptemp2(), creating a fifo with a templated
  name (like mkptemp) but with options for O_NONBLOCK and O_CLOEXEC.
- New sysdep to test for chroot().