tzdata: Revert to the "fat" "bloated" format

The timezone dumps have switched to a "slim" format since 2020b.
This has broken various packages, including
 - go 1.4 (used for bootstrapping)
 - haskellPackages.tz
 - libical

The "fat" format can still be generated, as this commit shows.
It seems to create files that are *mostly* the slim versions with
some more data attached.

pkgs/data/misc/tzdata/default.nix

@@ -31,6 +31,7 @@ stdenv.mkDerivation rec {
     "MANDIR=$(man)/share/man"
     "AWK=awk"
     "CFLAGS=-DHAVE_LINK=0"
+    "CFLAGS+=-DZIC_BLOAT_DEFAULT=\\\"fat\\\""
     "cc=${stdenv.cc.targetPrefix}cc"
     "AR=${stdenv.cc.targetPrefix}ar"
   ];