cygwin.w32api-headers: init as mingw_w64_headers derivative

Co-authored-by: Brian McKenna <brian@brianmckenna.org>

pkgs/os-specific/cygwin/default.nix

@@ -14,5 +14,6 @@ makeScopeWithSplicing' {
       callPackage = self.callPackage;
     in
     {
+      w32api-headers = callPackage ./w32api { };
     };
 }

pkgs/os-specific/cygwin/w32api/default.nix

@@ -0,0 +1,35 @@
+{
+  lib,
+  stdenvNoCC,
+  windows,
+}:
+stdenvNoCC.mkDerivation (finalAttrs: {
+  pname = "w32api-headers";
+
+  inherit (windows.mingw_w64_headers)
+    version
+    src
+    ;
+
+  configureFlags = [ (lib.enableFeature true "w32api") ];
+
+  preConfigure = ''
+    cd mingw-w64-headers
+  '';
+
+  passthru = {
+    incdir = "/include/w32api/";
+    libdir = "/lib/w32api/";
+  };
+
+  meta = {
+    description = "MinGW w32api package for Cygwin";
+    inherit (windows.mingw_w64_headers.meta)
+      homepage
+      downloadPage
+      license
+      ;
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+    teams = [ lib.maintainers.corngood ];
+  };
+})