update patch extfs for diffutils 3.3 change

[mnk]

It seem this somewhat corner case was missed a few years ago.

The NEWS snippet:

A file name containing spaces, double quotes, backslashes or control
characters is now encoded in a diff header as a double-quoted C string
literal. The escape sequences \\, \", \a, \b, \f, \n, \r, \t, \v and
\ooo (a three-digit octal number between 0 and 255) are used.

So, this case isn't covered by patchfs.in, resulting sometimes in a non-working vfs getting created.

[mnk]

I don't know perl, following is just a result of googling.

It seems that putting following in patchfs_canonicalize_path makes things somewhat working (meaning they aren't broken in an obvious way, though can't say what happens for names actually starting with '"' or containing backslashes...though if I'm reading the snippet correctly, that shouldn't happen):

  $fname =~ s,^"(.*)"$,$1,;
  $fname =~ s[\\(?:([0-7]{1,3})|(.))] [defined($1) ? chr(oct($1)) : $2]eg;