Download and include scarlett2 firmware in flatpak

Fixes: #112.

src/scarlett2-firmware.c

@@ -265,7 +265,12 @@ static void enum_firmware_dir(const char *dir_name) {
 
 void scarlett2_enum_firmware(void) {
   init_best_firmware();
-  enum_firmware_dir(SCARLETT2_FIRMWARE_DIR);
+
+  const char *fw_dir = getenv("SCARLETT2_FIRMWARE_DIR");
+
+  if (!fw_dir)
+    fw_dir = SCARLETT2_FIRMWARE_DIR;
+  enum_firmware_dir(fw_dir);
 }
 
 uint32_t scarlett2_get_best_firmware_version(uint32_t pid) {

vu.b4.alsa-scarlett-gui.yml

@@ -14,6 +14,8 @@ finish-args:
   - --socket=wayland
   # Needs access to ALSA device nodes:
   - --device=all
+  # Point to the firmware directory
+  - --env=SCARLETT2_FIRMWARE_DIR=/app/lib/firmware/scarlett2
 modules:
   - name: alsa-scarlett-gui
     buildsystem: simple
@@ -26,3 +28,13 @@ modules:
       # - type: git
       #   url: https://github.com/geoffreybennett/alsa-scarlett-gui.git
       #   tag: "0.2"
+
+  - name: scarlett2-firmware
+    buildsystem: simple
+    build-commands:
+      - mkdir -p $FLATPAK_DEST/lib/firmware/scarlett2
+      - cp -a LICENSE.Focusrite firmware/* $FLATPAK_DEST/lib/firmware/scarlett2
+    sources:
+      - type: archive
+        url: https://github.com/geoffreybennett/scarlett2-firmware/archive/refs/tags/2128b.tar.gz
+        sha256: 4a17fdbe2110855c2f7f6cfc5ea1894943a6e58770f3dff5ef283961f8ae2a03