Makefile.common: support inhibiting rule definitions
Makefile.common: support inhibiting rule definitions

BSP430 is intended to provide a board support package (hence BSP) capability
not only for standalone programs but for other infrastructure systems like
FreeRTOS and Contiki.  To allow BSP430 configuration to integrate with those
systems we need a way to allow their existing build rules to apply, while
still setting enough variables that those rules know what files need to be
built.

pabigot/bsp430,pabigot/bsp430,pabigot/bsp430,pabigot/bsp430