Support of external platforms

[forGGe]

There are a lot of platform definitions and platform-related entities exposed to the rest of the systems:

• memory layout and architecture
• linker script
• startup script
• peripheral headers
• console device

User must be able to override whole platform or some of its parts. This helps avoid adding every device with its own aspects of internal organization into theCore. If implemented, user will place platform module into own source-tree, out of theCore.

Example code:

set(CONFIG_PLATFORM_EXTERNAL ${PATH_TO_THE_EXTERNAL_PLATFORM_MODULE})

[rasendubi]

Check devicetree and alternatives. That may give some insight on what should be done.