Fix: Error: -exec [args...] + isn't supported yet. Only -exec [args...] ;

[sylvestre]

Error: -exec [args...] + isn't supported yet. Only -exec [args...] ;
example:
find . ! -newermt 'jan 01, 2000' -exec touch -d@1714807765 {} +

[hanbings]

Looks like what is mentioned at #6.
In addition to exec, it is also necessary to support the + syntax of execdir.