iperf3: Update to version 3.9

iperf3: Update to version 3.9

- Update iperf3 from 3.7 to 3.9
- No changes to rootfiles
- Update patch file to remove pg flag
- Release notes from version 3.8 onwards:-

iperf 3.9 2020-08-17
--------------------
* Notable user-visible changes
  * A --timestamps flag has been added, which prepends a timestamp to
    each output line.  An optional argument to this flag, which is a
    format specification to strftime(3), allows for custom timestamp
    formats (#909, #1028).
  * A --server-bitrate-limit flag has been added as a server-side
    command-line argument.  It allows a server to enforce a maximum
    throughput rate; client connections that specify a higher bitrate
    or exceed this bitrate during a test will be terminated.  The
    bitrate is expressed in bits per second, with an optional trailing
    slash and integer count that specifies an averaging interval over
    which to enforce the limit (#999).
  * A bug that caused increased CPU usage with the --bidir option has
    been fixed (#1011).
* Notable developer-visible changes
  * Fixed various minor memory leaks (#1023).

iperf 3.8.1 2020-06-10
----------------------
* Notable user-visible changes
  * A regression with "make install", where the libiperf shared
    library files were not getting installed, has been fixed (#1013 /
    #1014).

iperf 3.8 2020-06-08
--------------------
* Notable user-visible changes
  * Profiled libraries and binaries are no longer built by default
    (#950).
  * A minimal Dockerfile has been added (#824).
  * A bug with burst mode and unlimited rate has been fixed (#898).
  * Configuring with the --enable-static-bin flag will now cause
    a statically-linked iperf3 binary to be built (#989).
  * Configuring with the --without-sctp flag will now prevent SCTP
    from being auto-detected (#1008).  This flag allows building a
    static binary (see above item) on a CentOS system with SCTP
    installed, because no static SCTP libraries are available.
  * Clock skew between the iperf3 client and server will no longer
    skew the computation of jitter during UDP tests (#842 / #990).
  * A possible buffer overflow in the authentication feature has been
    fixed.  This was only relevant when configuration authentication
    using the libiperf3 API, and did not affect command-line usage.
    Various other improvements and fixes in this area were also made
    (#996).
* Notable developer-visible changes
  * The embedded version of cJSON has been updated to 1.7.13 (#978).
  * Some server authentication functions have been added to the API
    (#911).
  * API access has been added to the connection timeout parameter
    (#1001).
  * Tests for some authentication functions have been added.
  * Various compiler errors and warnings have been fixed.

Signed-off-by: Adolf Belka <ahb.ipfire@gmail.com>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>