* Remove SPEC declarations from mk/spec
* Remove all board-specific REQUIRE declaratiions left
* Replace [have_spec <board>] run-script declarations with have_board where necessary
* Remove addition of BOARD variable to SPECS in toplevel Makefile
* Move board-specific directories in base-hw out of specs
The script takes the following RUN_OPT parameters:
--image-muen-external-build Muen system is built automatically or externally
--image-muen-system Muen system policy
--image-muen-components Muen system components
--image-muen-hardware Muen hardware platform
--image-muen-gnat-path Path to GNAT toolchain
--image-muen-spark-path Path to SPARK toolchain