Change pmap_enter(9) interface to take flags parameter and superpage
mapping size (currently unused).  The flags includes the fault access
bits, wired flag as PMAP_ENTER_WIRED, and a new flag
PMAP_ENTER_NOSLEEP to indicate that pmap should not sleep.

For powerpc aim both 32 and 64 bit, fix implementation to ensure that
the requested mapping is created when PMAP_ENTER_NOSLEEP is not
specified, in particular, wait for the available memory required to
proceed.

In collaboration with:	alc
Tested by:	nwhitehorn (ppc aim32 and booke)
Sponsored by:	The FreeBSD Foundation and EMC / Isilon Storage Division
MFC after:	2 weeks
sed(1): Don't force a newline on last line, if input stream doesn't have one

While here, change how we check if the current line is the last one.
Before, we just checked if there were more files after the current one.
Now, we check the actual content of those files: they files may not have
a line at all. This matches the definition of the "last line" by the
Open Group.

The new behavior is closer to GNU sed.

PR:		160745
Phabric:	https://phabric.freebsd.org/D431
Reviewed by:	jilles
Approved by:	jilles
Exp-run by:	antoine