gnunet: update to version 0.19.2

GNUnet has not been updated for a while due to the gnurl-situation.
Now that we got libcurl-gnutls, we can update GNUnet.
For details, please see the GNUnet release notes:

https://www.gnunet.org/en/news/2022-09-0.17.6.html
https://www.gnunet.org/en/news/2022-10-0.18.0.html
https://www.gnunet.org/en/news/2022-11-0.18.1.html
https://www.gnunet.org/en/news/2022-12-0.19.0.html
https://www.gnunet.org/en/news/2022-12-0.19.1.html
https://www.gnunet.org/en/news/2023-01-0.19.2.html

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

net/gnunet/patches/020-curl-no-runtime-test.patch

@@ -0,0 +1,16 @@
+--- a/configure.ac
++++ b/configure.ac
+@@ -727,12 +727,7 @@ LIBCURL_CHECK_CONFIG([], [7.34.0], [],
+ 
+ OLD_LIBS=$LIBS
+ LIBS="$LIBS $LIBCURL"
+-AC_RUN_IFELSE(
+-     [AC_LANG_PROGRAM([[#include <curl/curl.h>]],
+-                      [[return (CURLSSLSET_OK != curl_global_sslset(CURLSSLBACKEND_GNUTLS, NULL, NULL));]])],
+-                    [curl_gnutls=1],
+-                    [AC_MSG_WARN([cURL does not have GnuTLS backend])
+-                     curl_gnutls=0])
++curl_gnutls=1
+ LIBS=$OLD_LIBS
+ AM_CONDITIONAL([HAVE_GNUTLS_CURL], [test "x$curl_gnutls" = "x1"])
+ AC_SUBST([curl_gnutls])