>[me@treeroot:~/rawr]$ cat it.nix 
{
  nixpkgs ? import <nixpkgs> {},
  pkgs ? nixpkgs.pkgsCross.mingwW64,
  stdenv ? pkgs.stdenv
}:
let
  mysdl = pkgs.callPackage ./sdl2.nix {};
in
stdenv.mkDerivation rec {
  name ="it";

  nativeBuildInputs = [ 
    nixpkgs.meson 
    nixpkgs.ninja
    nixpkgs.pkg-config ];
  buildInputs = [ 
    mysdl ];

  src = ./.;
}
>[me@treeroot:~/rawr]$ cat sdl2.nix
{
  nixpkgs ? import <nixpkgs> {} ,
  pkgs ? nixpkgs.pkgsCross.mingwW64,
  stdenv ? pkgs.stdenv,
  fetchurl ? pkgs.fetchurl,
} :
stdenv.mkDerivation rec {
  pname = "SDL2";
  version = "2.0.12";
  src = fetchurl {
    url = "https://www.libsdl.org/release/${pname}-${version}.tar.gz";
    sha256 = "0qy8wbqvfkb5ps8kxgaaf2zzpkjqbsw712hlp74znbn0jpv6i4il";
  };

  buildInputs = [ ];

  meta = with stdenv.lib; {
    description = "SDL2 for windows";
  };
}
>[me@treeroot:~/rawr]$ cat meson.build 
project('itd', 'c')
sdldep = dependency('sdl2')
executable('itd', 'main.c', dependencies: sdldep, install : true) 
>[me@treeroot:~/rawr]$ cat 
it.nix       main.c       meson.build  result/      sdl2.nix     
>[me@treeroot:~/rawr]$ cat main.c
#include <stdio.h>
#include <stdlib.h>

int main() {
  printf("He\n");
  return 0;
}

>[me@treeroot:~/rawr]$ nix build -f it.nix --show-trace --verbose
building '/nix/store/sx5rs338mab2ncw9sl83ijzy2w80lm94-it-x86_64-w64-mingw32.drv'...
builder for '/nix/store/sx5rs338mab2ncw9sl83ijzy2w80lm94-it-x86_64-w64-mingw32.drv' failed with exit code 1; last 10 log lines:
  Build targets in project: 1
  Found ninja-1.9.0 at /nix/store/32s826g956kqlglvnmx7d1vkyfwj69a4-ninja-1.9.0/bin/ninja
  meson: enabled parallel building
  building
  build flags: -j8 -l8
  [2/2] Linking target itd.d@exe/main.c.o'.
  FAILED: itd 
  /nix/store/1v0410l20p343l6cvpijz8bi4if2ysh6-gcc-wrapper-9.2.0/bin/cc  -o itd 'itd@exe/main.c.o' -Wl,--as-needed -Wl,--no-undefined -Wl,--start-group /nix/store/vp7rg0im453lrz6m8gj9nf50k724wq2z-SDL2-2.0.12-x86_64-w64-mingw32/lib/libSDL2main.a -mwindows -L/nix/store/vp7rg0im453lrz6m8gj9nf50k724wq2z-SDL2-2.0.12-x86_64-w64-mingw32/lib -lmingw32 -lSDL2 -Wl,--end-group
  gcc: error: unrecognized command line option '-mwindows'
  ninja: build stopped: subcommand failed.

let 
  pkgs = (import <nixpkgs> {}).pkgsCross.mingwW64;
in pkgs.callPackage ./it.nix { sdl2 = pkgs.callPackage ./sdl2.nix { }; }

{ stdenv, meson, ninja, pkg-config, sdl2 }:
stdenv.mkDerivation rec {
  name ="it";

  nativeBuildInputs = [ 
    meson 
    ninja
    pkg-config ];
  buildInputs = [ 
    sdl2 ];

  src = ./.;
}