tzdata: enable cross-compilation for Windows

* Additional make flags are needed since some functions do not exist
    or have different names or parameters on Windows.

  * When compiling for Windows, GCC implicitly adds a `.exe` suffix to
    the output file name. A patch is needed for the `install` target
    to locate and install the correct files.

  * The tzdata Makefile contains `zic` and `ZIC` variables. The former
    refers to the path of the program to execute, while the latter
    invokes the former with additional arguments (it is defined as
    `ZIC=$(zic) $(ZFLAGS)`, `ZFLAGS` is normally empty).

    Previously, `ZIC` was overridden, potentially loosing `ZFLAGS`
    arguments. This commit changes it to override `zic` instead.

  * The `zic` program is built and installed as part of the package and
    also executed during the build to translate time-related files. When
    cross-compiling it means that two executables need to be compiled:
    one to get installed and run on the host platform, and another to
    run on the build platform. Instead of renaming files and building a
    temporary executable for the build platform, this commit references
    the build platform's `tzdata.bin` package and runs its `zic`
    program.

pkgs/data/misc/tzdata/0001-Add-exe-extension-for-MS-Windows-binaries.patch

@@ -0,0 +1,15 @@
+diff --git a/Makefile b/Makefile
+index a9a989e..4da737b 100644
+--- a/Makefile
++++ b/Makefile
+@@ -579,8 +579,8 @@ install:	all $(DATA) $(REDO) $(MANS)
+ 			-t '$(DESTDIR)$(TZDEFAULT)'
+ 		cp -f $(TABDATA) '$(DESTDIR)$(TZDIR)/.'
+ 		cp tzselect '$(DESTDIR)$(BINDIR)/.'
+-		cp zdump '$(DESTDIR)$(ZDUMPDIR)/.'
+-		cp zic '$(DESTDIR)$(ZICDIR)/.'
++		cp zdump.exe '$(DESTDIR)$(ZDUMPDIR)/.'
++		cp zic.exe '$(DESTDIR)$(ZICDIR)/.'
+ 		cp libtz.a '$(DESTDIR)$(LIBDIR)/.'
+ 		$(RANLIB) '$(DESTDIR)$(LIBDIR)/libtz.a'
+ 		cp -f newctime.3 newtzset.3 '$(DESTDIR)$(MANDIR)/man3/.'

pkgs/data/misc/tzdata/default.nix

@@ -17,6 +17,10 @@ stdenv.mkDerivation rec {
 
   sourceRoot = ".";
 
+  patches = lib.optionals stdenv.hostPlatform.isWindows [
+    ./0001-Add-exe-extension-for-MS-Windows-binaries.patch
+  ];
+
   outputs = [ "out" "bin" "man" "dev" ];
   propagatedBuildOutputs = [];
 
@@ -34,22 +38,17 @@ stdenv.mkDerivation rec {
     "CFLAGS+=-DZIC_BLOAT_DEFAULT=\\\"fat\\\""
     "cc=${stdenv.cc.targetPrefix}cc"
     "AR=${stdenv.cc.targetPrefix}ar"
+  ] ++ lib.optionals stdenv.hostPlatform.isWindows [
+    "CFLAGS+=-DHAVE_DIRECT_H"
+    "CFLAGS+=-DHAVE_SYMLINK=0"
+    "CFLAGS+=-DRESERVE_STD_EXT_IDS"
   ];
 
-  depsBuildBuild = [ buildPackages.stdenv.cc ];
-
   doCheck = false; # needs more tools
 
-  installFlags = [ "ZIC=./zic-native" ];
-
-  preInstall = ''
-     mv zic.o zic.o.orig
-     mv zic zic.orig
-     make $makeFlags cc=${stdenv.cc.nativePrefix}cc AR=${stdenv.cc.nativePrefix}ar zic
-     mv zic zic-native
-     mv zic.o.orig zic.o
-     mv zic.orig zic
-  '';
+  installFlags = lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
+    "zic=${buildPackages.tzdata.bin}/bin/zic"
+  ];
 
   postInstall =
     ''