Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Whitespace fixes.

Bring support in for Intel Wired for Management 1.1 (PXE 0.99 and
below). This did not work previously because interrupts were
disabled when PXE calls were being made, and they must be enabled.
This should also allow us to be compliant with all newer PXE rom's
from Intel.

For PXE 0.99, this has been tested using the Intel N440BX motherboard
and I am confident it will work on the Intel L440GX motherboard.

Lots of help/information from: jhb, peter

I would like to thank Michael Johnston <michael.johnston@intel.com>,
Mike Henry <mike.henry@intel.com>, and all the other PXE developers
at Intel for their help, and information in helping solve this
problem.

Use !PXE api over PXENV+ api.
Magic trampoline by: peter (at 4am and after a good whipping at airhockey)
Do a better job of returning and detecting errors.