Use os.lstat in findall to correctly detect symlinked directories

[bysiber]

Summary

Manifest.findall() uses os.stat() which follows symlinks, making the S_ISLNK(mode) check dead code — symlinked directories are always traversed.

Problem

stat = os.stat(fullname)
mode = stat.st_mode
if S_ISREG(mode):
    allfiles.append(fsdecode(fullname))
elif S_ISDIR(mode) and not S_ISLNK(mode):
    push(fullname)

os.stat() follows symbolic links, so stat.st_mode always reflects the target of the symlink, never the symlink itself. S_ISLNK(mode) can only return True when the mode comes from os.lstat(), which returns info about the link itself.

As a result, symlinked directories are always added to the traversal stack. With circular symlinks (e.g. a directory that symlinks to a parent), this leads to infinite recursion.

Fix

Use os.lstat() instead of os.stat() so that S_ISLNK(mode) works as intended.