Problem: clipboard provider callback can be called recursively, leading
to E132: Function call depth is higher than 'maxfuncdepth'
Solution: Prevent recursive calls of
clip_provider_copy()/clip_provider_paste() (Foxe Chen).
closes: #20213
Signed-off-by: Foxe Chen <chen.foxe@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>