scripts/build-deb: support preparing sources via the script

In order to build upstream mesa snapshot we need to manually prepare
source directory. Add support for using the external script instead of
just fetching the dsc from Debian.

Signed-off-by: Dmitry Baryshkov <[email protected]>

Author: lumag

scripts/build-deb.py

@@ -59,8 +59,24 @@
         )
     print("✅ Checksum of original source package matched.")
 
-    # Unpack the source package
-    subprocess.run(['dpkg-source', '-x', dsc_file], cwd=temp_dir, check=True)
+    script = config.get('script')
+    if script:
+        if not os.path.isabs(script):
+            config_dir = os.path.dirname(args.config)
+            script = os.path.abspath(os.path.join(config_dir, script))
+
+        env = os.environ.copy()
+        env['DSC_FILE'] = dsc_file
+        env.update(config.get('env', {}))
+
+        subprocess.run(script, cwd=temp_dir, check=True, env=env)
+
+        print("✅ Successfully executed the script.")
+    else:
+        # Unpack the source package
+        subprocess.run(['dpkg-source', '-x', dsc_file],
+                       cwd=temp_dir,
+                       check=True)
 
     # Find the unpacked directory
     unpacked_dirs = [