Commit 9c214ed updated this function, and
replaced syscall.Dup2() for golang.org/x/sys/unix.Dup2(), which is not
available on Windows.

This patch splits the API from the implementation, and moves the unix
implementation to a "unix" file; a stub is added for Windows.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

This copies the github.com/containerd/containerd/sys.IsFifo() utility,
which is used in tandem with other functionality from this module, so
I thought it made sense to combine them here.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

exclude OpenFifoDup2() on Windows

Add IsFifo() utility

This reverts commit 14d8313.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Signed-off-by: Sebastiaan van Stijn <[email protected]>

This caused builds on Windows to fail, and no work is done on Solaris builds,
so we might as wel remove this code

    typechecking error: D:\\a\\fifo\\fifo\\src\\github.com\\containerd\\fifo\\mkfifo_nosolaris.go:24:17: Mkfifo not declared by package syscall

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Previous attempts to exclude more granular failed, so excluding most/all files on windows

    typechecking error: D:\\a\\fifo\\fifo\\src\\github.com\\containerd\\fifo\\handle_nolinux.go:34:19: Stat_t not declared by package syscall
    typechecking error: D:\\a\\fifo\\fifo\\src\\github.com\\containerd\\fifo\\handle_nolinux.go:35:20: Stat not declared by package syscall
    typechecking error: D:\\a\\fifo\\fifo\\src\\github.com\\containerd\\fifo\\raw_test.go:220:27: cannot use int(fd) (value of type int) as syscall.Handle value in argument to syscall.Write
    typechecking error: D:\\a\\fifo\\fifo\\src\\github.com\\containerd\\fifo\\raw_test.go:240:26: cannot use int(fd) (value of type int) as syscall.Handle value in argument to syscall.Read

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Fix linting, remove solaris code, and exclude files on Windows

Mostly to catch if we correctly specified build-tags

Signed-off-by: Sebastiaan van Stijn <[email protected]>