Is there a way to figure out which deps would have to be build from sources

[MK-MacPorts at techno.ms]

Hi devs,

I just wonder whether someone out there
	has already written some script
		which can determine for any given port A
			whether non-binary ports B1-Bn are to be build during port A's installation.

Greets,
Marko

P.S.: I do know that there is mp-distributable.sh in order to determine whether a port is binary-distributable.