bug#16133: 24.3; copy-file fails on chmod when copying to FAT filesystem

[Paul Eggert]

Artem Chuprina wrote:
> When the target file exists, cp does
> not try unless explicitly asked to.  But when creating file, it does
> (that is, file's permissions are copied from source, not just left as
> set by umask).

Even when creating a file, GNU cp by default does not use 'chmod'
to copy the file's permissions (12 bits).  Instead, it merely
creates the file with the permissions of the source
as modified by the umask (9 bits).  That is why it doesn't
run into a problem in your setup.

The proposed patch would cause GNU Emacs to act similarly,
which is why I expect it to work for you.