This includes some fixes for the ez80 build including:
1. Ability to handle decorated object file names,
2. Ability to handle libraries described with absolute paths
This commit address only the POSIX build and needs to be updated
for the Windows native build.
arch/z80/arc/ez80/Toolchain.sh: Move more common toolchain definitions from Make.defs.
boards/z80/ez80/scripts/eZ80_Config.mk: Move common defines that override tools/Config.mk to this new file.
This does not solve the ez80 build problem yet but does assure that when the solution is in place, it will automatically apply to all present and future ez80 configurations.