build: try removing junctions before calling git clean

See https://github.com/msys2/msys2-autobuild/issues/108#issuecomment-2776420879

It looks like git can under some circumstances hang forever when trying
to clean the checkout when there are junction loops. So try to remove
them manually before calling git clean.

Fixes #108

msys2_autobuild/build.py

@@ -163,6 +163,15 @@ def reset_git_repo(path: PathLike):
 
     def clean():
         assert os.path.exists(path)
+
+        # Try to avoid git hanging in a junction loop, by removing them
+        # before running git clean/reset
+        # https://github.com/msys2/msys2-autobuild/issues/108#issuecomment-2776420879
+        try:
+            remove_junctions(path)
+        except OSError as e:
+            print("Removing junctions failed", e)
+
         check_call(["git", "clean", "-xfdf"], cwd=path)
         check_call(["git", "reset", "--hard", "HEAD"], cwd=path)