Add option to choose between read-write and write-only mode [rt.cpan.org #99444]

[xdg]

https://rt.cpan.org/Ticket/Display.html?id=99444

File::Temp currently opens temporary files with O_RDWR. This makes it impossible to use it with PerlIO::gzip (i.e. set binmode gzip) because the latter only works with read-only or write-only file descriptors. Therefore it would be very useful to have an option to set write-only mode. I don't think that read-only would make much sense because then you could only read from an empty file.

[Leont]

Sounds reasonable to me, having some way to pass the mode would be useful.