The patch is pretty trivial (minimal testing but don't see why it should not be stable). The value of $_ is saved and restored so you can change/use it in &wanted with impunity. Note as we are passing 3 values to the &wanted every time there will be a slowdown but this is probably (speculation) trivial compared to iterating over the directory tree.
$ diff Find.pm FindPatch.pm
1c1
< package File::Find;
---
> package File::FindPatch;
394c394
< { &$wanted_callback }; # protect against wild "next"
---
> { my $save=$_; &$wanted_callback($save,$name,$dir); $_=$
+save }; # protect against wild "next"
450c450
< { &$wanted_callback }; # protect against wild "next"
---
> { my $save=$_; &$wanted_callback($save,$name,$dir); $_=$
+save }; # protect against wild "next"
495c495
< { &$wanted_callback }; # protect against wild "next"
---
> { my $save=$_; &$wanted_callback($save,$name,$dir); $_
+=$save }; # protect against wild "next"
519c519
< { &$wanted_callback }; # protect against wild
+"next"
---
> { my $save=$_; &$wanted_callback($save,$name,$
+dir); $_=$save }; # protect against wild "next"
525c525
< { &$wanted_callback }; # protect against wild "nex
+t"
---
> { my $save=$_; &$wanted_callback($save,$name,$dir)
+; $_=$save }; # protect against wild "next"
$