Cap

To compile cap (https://cap.so/) from source, use the following devShell

flakeModuleArgs: {
  config.perSystem = perSystemArgs@{pkgs, ...}: let
    inherit (perSystemArgs) pkgs;
  in {
    devShells.default = pkgs.mkShell {

      buildInputs = [
        pkgs.apple-sdk_15
      ];

      nativeBuildInputs = [
        pkgs.xcbuildHook

        pkgs.nodejs_20
        pkgs.pkg-config
        pkgs.rustc
        pkgs.cargo
        pkgs.libiconv
        pkgs.openssl
        pkgs.ffmpeg
        pkgs.stdenv.cc
        pkgs.xcodebuild
        pkgs.apple-sdk_15
        pkgs.cmake
        pkgs.cctools
      ];

      # The shellHook is the most critical part. It forces the environment
      # to use the correct SDK, overriding the broken build script.
      shellHook = ''
        # Set variables for libraries that use pkg-config.
        export PKG_CONFIG_PATH="''${PKG_CONFIG_PATH:-}:${pkgs.openssl.dev}/lib/pkgconfig:${pkgs.ffmpeg}/lib/pkgconfig"

        # Add the linker path for non-framework libraries.
        export NIX_LDFLAGS="''${NIX_LDFLAGS:-} -L${pkgs.libiconv}/lib"

        # --- Force the Environment ---
        # This is the most important command. It overrides the SDKROOT environment
        # variable to force all build tools (especially xcodebuild) to use the
        # modern SDK we've included, ensuring it can find ScreenCaptureKit.h.
        export SDKROOT="${pkgs.apple-sdk}/SDKs/MacOSX.sdk"
      '';
    };
  };
}

and run the following commands

pnpm install
pnpm cap-setup
pnpm tauri:build

In macOS, this creates the .app file at ./target/release/bundle/macos/Cap - Development.app