A worktree may be locked if the linked working tree is stored
on a portable device which is not available.
@param reason Buffer to store reason in. If null no reason is stored.
@param wt Worktree to check
@return 0 when the working tree not locked, a value greater
than zero if it is locked, less than zero if there was an
error
Check if worktree is locked
A worktree may be locked if the linked working tree is stored on a portable device which is not available.
@param reason Buffer to store reason in. If null no reason is stored. @param wt Worktree to check @return 0 when the working tree not locked, a value greater than zero if it is locked, less than zero if there was an error