gnunet: update to 0.24.1

gnunet: update to 0.24.1

This is a new major release. It breaks protocol compatibility with the
0.23.x versions.

Please be aware that Git master is thus henceforth (and has been for a
while) INCOMPATIBLE with the 0.23.x GNUnet network, and interactions
between old and new peers will result in issues.

In terms of usability, users should be aware that there are still a
number of known open issues in particular with respect to ease of use,
but also some critical privacy issues especially for mobile users.

Also, the nascent network is tiny and thus unlikely to provide good
anonymity or extensive amounts of interesting information.
As a result, the 0.24.1 release is still only suitable for early
adopters with some reasonable pain tolerance. 

v0.24.1:

  - Fix crash in libgnunetpq when Postgresql database was restarted

  - Add configure and make functionality for new meson build
    (https://www.gnu.org/prep/standards/html_node/Configuration.html)

v0.24.0:

  - Meson is new default build system

  - JSON: split off libgnunetmhd from libgnunetjson, renaming various
    GNUNET_JSON_-symbols to GNUNET_MHD_-. Removes dependency of
    libgnunetjson on libmicrohttpd

OpenWrt package maintainer note:
Meson build is not yet fit for use in OpenWrt's cross build system.

Signed-off-by: Daniel Golle <redacted>