Change the build system build module makefiles to have a set of sanity check macros they can call to verify user data. Add additional sanity checks.

Add optional CPPCHECK_FLAGS parameter to the CPPCHECK build module, for miscellaneous user flags. Ensure the user flags are applied after all auto-generated flags.

Add new ATPROGRAM build system module. Add ATPROGRAM and CPPCHECK modules to all application makefiles.