scripts: gen_dts_cmake: emit properties for /aliases

This enables cmake extensions that can look up the path for any
devicetree alias, or check if the alias is missing, etc.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>

scripts/dts/gen_dts_cmake.py

@@ -88,6 +88,13 @@ def main():
         path = chosen_nodes[node].path
         cmake_props.append(f'"DT_CHOSEN|{node}" "{path}"')
 
+    # The separate loop over edt.nodes here is meant to keep
+    # all of the alias-related properties in one place.
+    for node in edt.nodes:
+        path = node.path
+        for alias in node.aliases:
+            cmake_props.append(f'"DT_ALIAS|{alias}" "{path}"')
+
     for node in edt.nodes:
         cmake_props.append(f'"DT_NODE|{node.path}" TRUE')