Fixes #72

- Using custom DNS internally (without TLS) to download Unbound files
- Using then Unbound with DNS over TLS internally and system wide
- Works even if you host system DNS is broken
- Waits a few milliseconds for Unbound to start up

internal/dns/wait.go

@@ -0,0 +1,20 @@
+package dns
+
+import (
+	"fmt"
+	"time"
+)
+
+func (c *configurator) WaitForUnbound() (err error) {
+	const maxTries = 10
+	const hostToResolve = "github.com"
+	for try := 1; try <= maxTries; try++ {
+		_, err := c.lookupIP(hostToResolve)
+		if err == nil {
+			return nil
+		}
+		c.logger.Warn("could not resolve %s (try %d of %d)", hostToResolve, try, maxTries)
+		time.Sleep(time.Duration(maxTries * 50 * time.Millisecond))
+	}
+	return fmt.Errorf("Unbound does not seem to be working after %d tries", maxTries)
+}