(cvs head) RTEMS makefiles broken

[Till Straumann]

The (legacy) RTEMS makefile system seems to be broken on the cvs head.

 - doesnt' work with multilibbed cpukit
 - new definitions of 'make-exe' & friends in 'leaf.cfg' cannot be
   overridden by make/custom/<bsp>.cfg because Makefile.inc
   includes 'leaf.cfg' after $(RTEMS_CUSTOM)

 - same applies for the DOWNEXT - all BSPs end up with '.ralf'

The last two problems could be fixed with the 'override' directive
but I don't think that's a desirable solution.

-- Till