It is frequent to see in Devicetree code constructs like:
```c
#define NAME_AND_COMMA(node_id) DT_NODE_FULL_NAME(node_id),
const char *child_names[] = {
DT_FOREACH_CHILD(DT_NODELABEL(n), NAME_AND_COMMA)
};
```
That is, an auxiliary macro to append a separator character in
DT_FOREACH* macros. Non-DT API, e.g. FOR_EACH(), takes a separator
argument to avoid such intermediate macros.
This patch adds DT_FOREACH_CHILD_SEP (and instance/status okay/vargs
versions of it). They all take an extra argument: a separator. With this
change, the example above can be simplified to:
```c
const char *child_labels[] = {
DT_FOREACH_CHILD(DT_NODELABEL(n), DT_NODE_FULL_NAME, (,))
};
```
Notes:
- Other DT_FOREACH* macros could/should be extended as well
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
fff9ecbc7f