dependencies/base: Correctly handle includes and sources in ExternalDependency
These were being ignored before now.
@@ -275,6 +275,10 @@ class ExternalDependency(Dependency):
new.link_args = []
if not sources:
new.sources = []
+ if not includes:
+ new.include_directories = []
+ if not sources:
+ new.sources = []
return new
