os/signal: deadlock detection fails when os/signal is included

go1.8, go1.9-rc2

linux amd64 & go playground

including `os/signal` breaks deadlock detection:

~~~go
package main

import _ "os/signal"

func main() {
	c := make(chan int)
	c <- 1
}
~~~

or see https://play.golang.org/p/-KF7aAeIhS as it happens there as well

this hangs

without `os/signal` included we get the expected deadlock detection message