Allow XN file to be located outside the application source

[danielpieczko]

Feature request from @xalbertoisorna
Add a way to specify an XN file which is not in the application directory. The motivation for this is to be able to have a single copy of an XN file which is used by multiple applications in a repository.

Possible implementation:
The APP_HW_TARGET could take one of three forms:

1. a name which refers to an XN file shipped with the XTC Tools
2. a filename ending in .xn which can be searched for within the application source directory
3. a path to the XN file: eg. ${CMAKE_CURRENT_LIST_DIR}/../../shared/foo.xn

[ed-xmos]

I have just bumped into this too so a +1 from me!

[xross]

This feature request might help alleviate the issue: #137