{ ... }:

final: prev: {
  mesa = (prev.mesa.overrideAttrs (old: rec {
    version = "git-unstable-2026-02-12";
    src = prev.fetchFromGitLab {
      domain = "gitlab.freedesktop.org";
      owner = "mesa";
      repo = "mesa";
      rev = "main";
      hash = "sha256-5gpLORvbV3skALrQa0VxTJJarYjuq+KyTxDm9HtZNbQ=";
    };
    patches = [];
    buildInputs = old.buildInputs ++ (with prev.llvmPackages_21; [ 
      clang-unwrapped
      libclang
    ]);
    
    # Create symlinks to clang libraries so meson can find them
    preConfigure = (old.preConfigure or "") + ''
      mkdir -p $NIX_BUILD_TOP/clang-libs
      for lib in ${prev.llvmPackages_21.clang-unwrapped.lib}/lib/*.a; do
        ln -sf "$lib" "$NIX_BUILD_TOP/clang-libs/"
      done
      export LIBRARY_PATH="$NIX_BUILD_TOP/clang-libs:''${LIBRARY_PATH:-}"
      export CXXFLAGS="$CXXFLAGS -fno-strict-aliasing"
    '';
    
    mesonFlags = 
      (builtins.filter (flag: 
        !(prev.lib.hasPrefix "-Dclang-libdir=" flag) &&
        flag != "--sysconfdir=/etc"
      ) old.mesonFlags) ++ [
      "-Dsysconfdir=${placeholder "out"}/etc"
    ] ++ (if prev.stdenv.hostPlatform.is64bit then [ "-Dintel-rt=enabled" ] else [ "-Dintel-rt=disabled" ]);
  })).override {
    stdenv = prev.gcc14Stdenv;
  };
}