check for EINTR when calling waitpid.

ok jsing@
Fixes a resume time page table issue on amd64 if the piglet was located
above 1GB physical (caused by using an incorrect page size mask)

Also removes some unneeded low memory mappings on both amd64 and i386 (this
is a cosmetic fix but makes things easier to debug).
Delete an obsolete comment
Don't use the suspending kernel's VA mapping for the piglet. It's far
easier and much less error-prone to just identity map it in the resuming
kernel as we have more control over the VA space layout there (otherwise
we are at the mercy of the suspending kernel's placement of the piglet VA).

This diff also increases the size of the piglet to 4 chunks, to avoid an
overwrite issue seen in m2k14 where the start of the kernel text was
overwritten with a bounced chunk before unpack.
Minor cleanups in wording in some comments and printfs, and added some
dprintfs to help debugging in the field (disabled by default)
Print sizeof() value and size_t variable with %zu rather than %zd.
add <sys/filio.h> header for FIONBIO

ok beck@
We do have IP_OPTIONS; no obj change.
OK benno@
We do have SIGINFO; no obj change.
OK benno@
notdef is notdef since the beginning of time; no obj change.
OK benno@
We do have ICMP_MASKREQ & ICMP_MASKREPLY; no obj change.
OK benno@
We do have icmp_data; no obj change.
OK benno@
Kill unused route storages.

blambert@, henning@, lteo@
I hate eval. Apart from when it's really needed.
Eval'ing constant expressions is not such a case.

"...fine with me" krw@
spelling
use explicit_bzero for stack and freed variables
Adds an optional bus function to set the address of a new device and
explicitly set it when required.

Right now xhci(4) does not need such function because it assigns
addresses when the first pipe of a device is opened.

ok yuo@, pirofti@
Now that the stack handles properly the xhci(4) way of setting an
address, kill some no longer true comments and create a proper
function to assign an address.

For the moment, an address is assigned when setting up a slot for a
new device.
generate a locatedb while making release.
input and okay deraadt@
miod@ fixed the "bug" so remove reference to it in the man pod^Wpage.