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.

Added new JTAG_ENABLE() macro for the AVR8 architecture. Fixed the JTAG_DISABLE() macro clearing all other bits in MCUSR when called.

Moved the XPLAIN board specific bootloader entry condition code to the Application_Jump_Check() function of the DFU bootloader, added support for the original XPLAIN board to the CDC class bootloader.

Fix BUILD module so that user flags are applied after all auto-generated flags, ensure dependency files are generated with a .d extension rather than a .o.d extension, allow use of full part names ("at32uc3a0256") instead of GCC truncted part names ("uc3a0256").

Simplify AVRDUDE build module, ensure that the correct target names for FLASH and EEPROM writing are passed to the programmer tool.

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.

Strip out BuildTest sub-makefile contents as much as possible. Remove old UC3 build test makefile from the ModuleTest build test. Add platform module to the example LUFA makefile.

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

Add symbol-sizes target to the BUILD build system module to print a size-sorted list of symbols from a compiled application, in decimal bytes.

Add emergency aborts to the recursive makefiles to prevent system failures due to infinite recursion if something happens while building the project lists.

Don't show a list of object/dependency files in the human friendly output of the BUILD module clean command. Use a unique message prefix for assembling vs. compiling.

Switch StaticAnalysisTest build test to use the new build system CPPCHECK module. Update additional build tests to all include the core build system module.

Disable inbuilt make rules in the LUFA build system for speedups when compiling many projects recursively.

Add explicit blank checks in the build system for user-set but blank variables that must not be blank.

Add .PHONY targets in all build system modules. Alter BUILD module so that the existence of source files are checked before the build is started.

Add $(MAKEFILE_LIST) as a dependency on build rules that could be altered by changes to the makefiles - if the user alters the project makefile, require that all modules are rebuilt.

Rename program_ee AVRDUDE module target to program-ee. Update CORE build module to print out lists one item per line, rather than all on one line.

Clean up CORE build system module, use simple rather than recursive make variables for internal constants and $(shell) derived values.

Clean up BUILD build system module - seperate architecture utility prefix code and sanity check from the CC_FLAGS construction code. Add target to print GCC version.