The $srctree environment variable gives the path relative to which
'(o)source' statements work (the current directory is used if $srctree
is unset). It is set to $ZEPHYR_BASE in cmake/kconfig.cmake, so there's
no need to qualify the source of Kconfig.zephyr in sample Kconfig files
(or in external projects).
All 'source's in Zephyr assume that the Zephyr root directory is used as
the srctree as well, and would break otherwise.
Remove the $(ZEPHYR_BASE)s to make it clearer that all 'source'
statements work relative to the Zephyr root. There was some user
confusion on IRC.
Also explain how things work in the documentation.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
92ef8582b9