Generate temporary file name (string) starting with PREFIX (a string).
The Emacs process number forms part of the result,
so there is no danger of generating a name being used by another process.
In addition, this function makes an attempt to choose a name
which has no existing file. To make this work,
PREFIX should be an absolute file name.
There is a race condition between calling `make-temp-name' and creating the
file which opens all kinds of security holes. For that reason, you should
probably use `make-temp-file' instead, except in three circumstances:
* If you are creating the file in the user's home directory.
* If you are creating a directory rather than an ordinary file.
* If you are taking special precautions as `make-temp-file' does.
(fn PREFIX)