KiCad 4.0.7 update

Hi ports,

still engaged into my process of updating KiCad to 4.0.7 , i'm facing an issue with boost_context .
from the boost makefile :

 # 'context' and 'coroutine' use MD bits and miss support for Alpha, PA-RISC, SPARC and SuperH.
The author does not care about adding support for Alpha and PA-RISC.

KiCad 4.0.7 configure requires boost_context and i can't figure out what is « MD bits » even after some
googling. rsadowski@ is still working on a boost update and as far as i saw , FreeBSD did not locked the thing.
Maybe someone has some info about these « MD bits » and the arch limitations it brings?

Anyway I'd like to know how to behave to handle properly this issue.

Thanks for your time,

Best regards,
Jerome