Fix use after free bug.
Parse_SetInput:
curFile->fname was using the buffer passed to it - which ReadMakefile frees.
This change makes the comment in ParseEOF about leaking curFile->fname true.
Remove stray empty line.

MFC after:	3 days
Since the gem pagefault handler relocks the vm object lock, other
thread might fault on the same GTT offset meantime and instantiate the
mapping.  Recheck that the mgt device object still does not have a
page at the current offset after relocking, and return a possibly
installed page.

Reported by:	Oleg Sidorkin <osidorkin@gmail.com>
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
On some generations of the Intel GPU, disabling of the VGA Display
stops updating the vertical retrace indicator.  The text mouse
renderer in syscons is executing from the callout and spins waiting
for the start of next frame.  As result, after the X server finishes,
since the VGA cannot be turned on, but syscons does not know about
this, the clock swi spins forever.

Hack around the problem by disabling wait for the retrace if KMS is
activated.

Diagnosed and tested by:	Michiel Boland <boland37@xs4all.nl>
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks