sync with the version in head (r274338):
fix one comment, and return kernel-supplied error if available.
no API changes.

Update a couple of header files that were missed in r270252. This is a
direct commit to stable/10.

Submitted by: luigi

MFC 267168:
misc bugfixes:
- stdio.h is needed for fprint()
- make memsize uint32_t to avoid errors due to overflow
- honor the *XPOLL flagg in NIOCREGIF requests
- mmap fails wit MAP_FAILED, not NULL.

MFH: sync the netmap code with the one in HEAD
(enhanced VALE switch, netmap pipes, emulated netmap mode).
See details in the log for svn 261909.

sync with the version in head (r274338):
fix one comment, and return kernel-supplied error if available.
no API changes.

Update a couple of header files that were missed in r270252. This is a
direct commit to stable/10.

Submitted by: luigi

MFC 267168:
misc bugfixes:
- stdio.h is needed for fprint()
- make memsize uint32_t to avoid errors due to overflow
- honor the *XPOLL flagg in NIOCREGIF requests
- mmap fails wit MAP_FAILED, not NULL.

MFH: sync the netmap code with the one in HEAD
(enhanced VALE switch, netmap pipes, emulated netmap mode).
See details in the log for svn 261909.