creating a temporary fifo (tmpfile but for fifo)

[Timothee Cour via Digitalmars-d]

> I believe the recommended function for this is mkstemp. [1]

Mkstemp creates a regular file, not a fifo

>> * could we allow specifying a directory name for tmpfile?

> Yes, using mkdtemp. [2]

I meant adding a D api to add a temp file rooted under a specified
directory; the C api's allow that but not tempfile