Cleanup: Move scene.c to C++

This is meant to allow using C++ data structures in this file
as a performance improvement. Particularly `Vector` instead
of `ListBase` for `duplilist`. This change builds and passes
tests on all platforms on the buildbot.

source/blender/blenkernel/BKE_lib_id.h

@@ -515,7 +515,7 @@ void BKE_main_id_flag_listbase(struct ListBase *lb, int flag, bool value);
 void BKE_main_id_flag_all(struct Main *bmain, int flag, bool value);
 
 /**
- * Next to indirect usage in `readfile.c/writefile.c` also in `editobject.c`, `scene.c`.
+ * Next to indirect usage in `readfile.c/writefile.c` also in `editobject.c`, `scene.cc`.
  */
 void BKE_main_id_newptr_and_tag_clear(struct Main *bmain);
 

source/blender/blenkernel/CMakeLists.txt

@@ -247,7 +247,7 @@ set(SRC
   intern/preferences.c
   intern/report.c
   intern/rigidbody.c
-  intern/scene.c
+  intern/scene.cc
   intern/screen.c
   intern/shader_fx.c
   intern/shrinkwrap.c

source/blender/makesdna/DNA_scene_types.h

@@ -1990,7 +1990,7 @@ enum {
 
 /* sequencer seq_prev_type seq_rend_type */
 
-/** #RenderData.engine (scene.c) */
+/** #RenderData.engine (scene.cc) */
 extern const char *RE_engine_id_BLENDER_EEVEE;
 extern const char *RE_engine_id_BLENDER_WORKBENCH;
 extern const char *RE_engine_id_CYCLES;

source/blender/render/intern/render_result.c

@@ -402,7 +402,7 @@ RenderResult *render_result_new(Render *re,
       render_layer_add_pass(rr, rl, 4, RE_PASSNAME_COMBINED, view, "RGBA", false);
     }
 
-    /* NOTE: this has to be in sync with `scene.c`. */
+    /* NOTE: this has to be in sync with `scene.cc`. */
     rl->layflag = SCE_LAY_FLAG_DEFAULT;
     rl->passflag = SCE_PASS_COMBINED;