Do explicit mirror resolve with curl

host suddenly doesn't understands hostname with https://. I'm not sure
it did before, it could be DNS server doing some magic.

build-host.sh

@@ -128,7 +128,7 @@ function main() {
   expect "# "
 
   # Explicitly lookup mirror address as we'd get random failures otherwise during pacman
-  send "host ${MIRROR}\n"
+  send "curl -sSo /dev/null ${MIRROR}\n"
   expect "# "
 
   # Install required packages