3.4.0-rc2 fails to build (test failures)

[Bas Couwenberg]

The ​Debian package build for 3.4.0-rc2 fails due to test failures:

 /<<PKGBUILDDIR>>/regress/core/flatgeobuf .. failed (diff expected obtained: /tmp/pgis_reg/test_17_diff)
-----------------------------------------------------------------------------
--- ./regress/core/flatgeobuf_expected	2023-08-12 06:12:41.000000000 +0000
+++ /tmp/pgis_reg/test_17_out	2023-08-12 08:58:31.031006772 +0000
@@ -1,3 +1,4 @@
+ERROR:  invalid value for parameter "TimeZone": "utc"
 --- Null geometry ---
 T1|0|
 --- Geometry roundtrips ---
-----------------------------------------------------------------------------

Full buildlog: ​amd64, ​arm64, ​ppc64el

The build is using tzdata (2023c-8) which contains this change:

   * Ship only timezones in tzdata that follow the current rules of geographical
     region (continent or ocean) and city name. Move all legacy timezone symlinks
     (that are upgraded during package update) to tzdata-legacy. This includes
     dropping the special handling for US/* timezones. (Closes: #1040997)

tzdata (2023c-9) moved UTC back:

   * Move top-level UTC timezone back to tzdata (Closes: #1043250, LP: #2030684)

tzdata (2023c-10) reverted more changes:

   * Partially revert 2023c-8: Move top-level timezones like UTC and CET back to
     tzdata. Only the old or merged timezones mentioned in the upstream backward
     file stay in tzdata-legacy (Closes: #1043250, LP: #2030684)

The test failure might be resolved once tzdata >= 2023c-9 is used by the build daemons.