cmake: Always create missing includes in build dir

There really isn't any reason to not always create missing
include directories inside the build dir. Just restricting
this to generate generated sources should work in an ideal
world, however, there exists lots of suboptimal CMake code
where this assumption is not always true.

mesonbuild/cmake/interpreter.py

@@ -435,10 +435,7 @@ class ConverterTarget:
             x = x.resolve()
             assert x.is_absolute()
             if not x.exists() and not any([x.name.endswith(y) for y in obj_suffixes]) and not is_generated:
-                if (
+                if path_is_in_root(x, Path(self.env.get_build_dir()), resolve=True):
-                    any([path_is_in_root(root_src_dir / y, x.resolve(), resolve=True) for y in self.generated_raw])
-                        and path_is_in_root(x, Path(self.env.get_build_dir()), resolve=True)
-                    ):
                     x.mkdir(parents=True, exist_ok=True)
                     return x.relative_to(Path(self.env.get_build_dir()) / subdir)
                 else: