from jared rr spiegel, closes PR 4982, ok beck@

As discussed with espie@, ok millert@

fixes pr #4996, from joachim schipper;

ok henning@

ok beck@ kettenis@ norby@

has a rdo on $int_if that stops working then. pt out by cedric

openwall.com, ok henning@

"yes, that is correct." jmc@ (a while back)

tell user to get it through stdint.h (note old sys/types.h still works,
for now).
okay millert@, jmc@

is reentrant in its current implementation anyway.
Surfing on the recent major version bump, ok millert@ deraadt@

Remove an extraneous check for dtoa returning Inf/Nan

Decimal point was missing for some exponential output
Only divide sign by 10 once per loop
Add a missing NUL terminator for one case
If there is no whole number portion, print a leading zero (e.g. 0.1 not .1)

1997 (yes, really).

Add new sys/_types.h header
Include machine/_types.h or sys/_types.h where applicable

drivers, and to wscons as the console; a few parts borrowed from OpenBSD/macppc
as well.
Currently only working with displays configured in 1bpp or 8bpp modes; this
limitation will be worked on ASAP.
Tested by claudio@ kettenis@ martin@ nick@ and I on various models. X11 changes
coming soon.

Use correct values for _POSIX_TTY_NAME_MAX and _POSIX_LOGIN_NAME_MAX
Define MAXLOGNAME in terms of LOGIN_NAME_MAX
OK krw@

separate errno.h.  sys/errno.h now only contains errno values (which
is included byerrno.h).  OK deraadt@

dev/fd comment and point to fd(4).

a long time, but i'm a bloody slacker...

OK deraadt@

in sys/cdefs.h) instead of _FOO_SOURCE.  Also fix several namespace
pollution issues, including the byte order defines.  OK deraadt@