vc1: Do not assume seek happens after decoding

If a seek is requested before the decoding start there is no
current picture.

CC: libav-stable@libav.org
x11grab: Check for XFixes availability at runtime
x11grab: Check XFixesGetCursorImage return value

It could return NULL if the cursor is outside the screen, the connection
timed out or the system is out of memory.

CC: libav-stable@libav.org
x11grab: Check the XQueryPointer return value

The paint_mouse_pointer() code uses XFixes to retrieve the cursor
coordinates, but XFixes gives no information about which screen the
pointer is on; this results in always drawing the cursor on the
captured screen even if the mouse pointer was on another screen.

For example, when capturing from screen 1 (i.e. -f x11grab -i ":0.1")
the cursor was being drawn in the captured image even when the mouse
pointer was actually on screen 0, which is wrong and visually confusing.

CC: libav-stable@libav.org
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
avformat/img2dec: Support -loop with pipes

Fixes Ticket3976

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '68211c70afcfd4d675029cc85fba7dee8de53bdf'

* commit '68211c70afcfd4d675029cc85fba7dee8de53bdf':
  vc1: Do not assume seek happens after decoding

See: 6801eb0a0981f113f5f09ed4799d9ae805af62a3
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '89fa2b5616274194d90bde0aeebf6adbd1245193'

* commit '89fa2b5616274194d90bde0aeebf6adbd1245193':
  x11grab: Check for XFixes availability at runtime

See: a65c0a3fe822386be30fd3371af9f0d008b02874
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '5b9c817dc7577b6d44acc94d73b9c77c52cda489'

* commit '5b9c817dc7577b6d44acc94d73b9c77c52cda489':
  x11grab: Check XFixesGetCursorImage return value

Conflicts:
	libavdevice/x11grab.c

See: a65c0a3fe822386be30fd3371af9f0d008b02874

The warning with adjusted text is kept from a65c0a3fe822386be30fd3371af9f0d008b02874
but drawing the cursor is not disabled in case XFixesGetCursorImage() fails

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '2a5ac99e6e06078713f684fee2466c91f677b303'

* commit '2a5ac99e6e06078713f684fee2466c91f677b303':
  x11grab: Check the XQueryPointer return value

Conflicts:
	libavdevice/x11grab.c

See: 69c34a6ac986e31b5286a1d566617ec25b93e6a7
Merged-by: Michael Niedermayer <michaelni@gmx.at>
avformat/img2dec: Attempt to detect non-escaped glob patterns too (-pattern_type glob)

Fixes ticket #3948

Based-on-patch-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Alexander Strasser <eclipse7@gmx.net>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>