Fixes the following security issues:

14.6.1:

* AST-2017-005 (applied to all released versions): The "strictrtp" option in
  rtp.conf enables a feature of the RTP stack that learns the source address
  of media for a session and drops any packets that do not originate from
  the expected address.  This option is enabled by default in Asterisk 11
  and above.  The "nat" and "rtp_symmetric" options for chan_sip and
  chan_pjsip respectively enable symmetric RTP support in the RTP stack.
  This uses the source address of incoming media as the target address of
  any sent media.  This option is not enabled by default but is commonly
  enabled to handle devices behind NAT.

  A change was made to the strict RTP support in the RTP stack to better
  tolerate late media when a reinvite occurs.  When combined with the
  symmetric RTP support this introduced an avenue where media could be
  hijacked.  Instead of only learning a new address when expected the new
  code allowed a new source address to be learned at all times.

  If a flood of RTP traffic was received the strict RTPsupport would allow
  the new address to provide media and with symmetric RTP enabled outgoing
  traffic would be sent to this new address, allowing the media to be
  hijacked.  Provided the attacker continued to send traffic they would
  continue to receive traffic as well.

* AST-2017-006 (applied to all released versions): The app_minivm module has
  an “externnotify” program configuration option that is executed by the
  MinivmNotify dialplan application.  The application uses the caller-id
  name and number as part of a built string passed to the OS shell for
  interpretation and execution.  Since the caller-id name and number can
  come from an untrusted source, a crafted caller-id name or number allows
  an arbitrary shell command injection.

* AST-2017-007 (applied only to 13.17.1 and 14.6.1): A carefully crafted URI
  in a From, To or Contact header could cause Asterisk to crash

For more details, see the announcement:
https://www.asterisk.org/downloads/asterisk-news/asterisk-11252-13171-1461-116-cert17-1313-cert5-now-available-security

14.6.2:

* AST-2017-008: Insufficient RTCP packet validation could allow reading
  stale buffer contents and when combined with the “nat” and “symmetric_rtp”
  options allow redirecting where Asterisk sends the next RTCP report.

  The RTP stream qualification to learn the source address of media always
  accepted the first RTP packet as the new source and allowed what
  AST-2017-005 was mitigating.  The intent was to qualify a series of
  packets before accepting the new source address.

For more details, see the announcement:
https://www.asterisk.org/downloads/asterisk-news/asterisk-11253-13172-1462-116-cert18-1313-cert6-now-available-security



Drop 0004-configure-in-cross-complation-assimne-eventfd-are-av.patch as this
is now handled differently upstream (by disabling eventfd for cross
compilation, see commit 2e927990b3d2 (eventfd: Disable during cross
compilation)).  If eventfd support is needed then this should be submitted
upstream.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
(cherry picked from commit 3f1d2c6c746a04d19a493f4e7b866e84e3aa7dc8)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>