Cleanup: Remove scene frame macros (`CFRA` et al.)

Removes the following macros for scene/render frame values:
- `CFRA`
- `SUBFRA`
- `SFRA`
- `EFRA`

These macros don't add much, other than saving a few characters when typing.
It's not immediately clear what they refer to, they just hide what they
actually access. Just be explicit and clear about that.
Plus these macros gave read and write access to the variables, so eyesores like
this would be done (eyesore because it looks like assigning to a constant):
```
CFRA = some_frame_nbr;
```

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D15311

4 files changed, 17 insertions, 17 deletions

diff --git a/source/blender/editors/io/io_alembic.c b/source/blender/editors/io/io_alembic.c
index 0e8e0f83597..0068586730f 100644
--- a/source/blender/editors/io/io_alembic.c
+++ b/source/blender/editors/io/io_alembic.c
@@ -144,10 +144,10 @@ static int wm_alembic_export_exec(bContext *C, wmOperator *op)
   /* Take some defaults from the scene, if not specified explicitly. */
   Scene *scene = CTX_data_scene(C);
   if (params.frame_start == INT_MIN) {
-    params.frame_start = SFRA;
+    params.frame_start = scene->r.sfra;
   }
   if (params.frame_end == INT_MIN) {
-    params.frame_end = EFRA;
+    params.frame_end = scene->r.efra;
   }
 
   const bool as_background_job = RNA_boolean_get(op->ptr, "as_background_job");
@@ -248,8 +248,8 @@ static void wm_alembic_export_draw(bContext *C, wmOperator *op)
   Scene *scene = CTX_data_scene(C);
 
   if (scene != NULL && RNA_boolean_get(op->ptr, "init_scene_frame_range")) {
-    RNA_int_set(op->ptr, "start", SFRA);
-    RNA_int_set(op->ptr, "end", EFRA);
+    RNA_int_set(op->ptr, "start", scene->r.sfra);
+    RNA_int_set(op->ptr, "end", scene->r.efra);
 
     RNA_boolean_set(op->ptr, "init_scene_frame_range", false);
   }
diff --git a/source/blender/editors/io/io_gpencil_export.c b/source/blender/editors/io/io_gpencil_export.c
index 6e5ae9f3cba..3f905dd7de0 100644
--- a/source/blender/editors/io/io_gpencil_export.c
+++ b/source/blender/editors/io/io_gpencil_export.c
@@ -153,9 +153,9 @@ static int wm_gpencil_export_svg_exec(bContext *C, wmOperator *op)
                             .v3d = v3d,
                             .ob = ob,
                             .mode = GP_EXPORT_TO_SVG,
-                            .frame_start = CFRA,
-                            .frame_end = CFRA,
-                            .frame_cur = CFRA,
+                            .frame_start = scene->r.cfra,
+                            .frame_end = scene->r.cfra,
+                            .frame_cur = scene->r.cfra,
                             .flag = flag,
                             .scale = 1.0f,
                             .select_mode = select_mode,
@@ -306,9 +306,9 @@ static int wm_gpencil_export_pdf_exec(bContext *C, wmOperator *op)
                             .v3d = v3d,
                             .ob = ob,
                             .mode = GP_EXPORT_TO_PDF,
-                            .frame_start = SFRA,
-                            .frame_end = EFRA,
-                            .frame_cur = CFRA,
+                            .frame_start = scene->r.sfra,
+                            .frame_end = scene->r.efra,
+                            .frame_cur = scene->r.cfra,
                             .flag = flag,
                             .scale = 1.0f,
                             .select_mode = select_mode,
diff --git a/source/blender/editors/io/io_gpencil_import.c b/source/blender/editors/io/io_gpencil_import.c
index 45f5441616f..9ac64407dcf 100644
--- a/source/blender/editors/io/io_gpencil_import.c
+++ b/source/blender/editors/io/io_gpencil_import.c
@@ -90,9 +90,9 @@ static int wm_gpencil_import_svg_exec(bContext *C, wmOperator *op)
       .v3d = v3d,
       .ob = NULL,
       .mode = GP_IMPORT_FROM_SVG,
-      .frame_start = CFRA,
-      .frame_end = CFRA,
-      .frame_cur = CFRA,
+      .frame_start = scene->r.cfra,
+      .frame_end = scene->r.cfra,
+      .frame_cur = scene->r.cfra,
       .flag = flag,
       .scale = scale,
       .select_mode = 0,
diff --git a/source/blender/editors/io/io_obj.c b/source/blender/editors/io/io_obj.c
index 53fa4788d0e..79ec7ebf2a5 100644
--- a/source/blender/editors/io/io_obj.c
+++ b/source/blender/editors/io/io_obj.c
@@ -208,11 +208,11 @@ static bool wm_obj_export_check(bContext *C, wmOperator *op)
     int end = RNA_int_get(op->ptr, "end_frame");
     /* Set the defaults. */
     if (start == INT_MIN) {
-      start = SFRA;
+      start = scene->r.sfra;
       changed = true;
     }
     if (end == INT_MAX) {
-      end = EFRA;
+      end = scene->r.efra;
       changed = true;
     }
     /* Fix user errors. */
@@ -266,7 +266,7 @@ void WM_OT_obj_export(struct wmOperatorType *ot)
                   "Export multiple frames instead of the current frame only");
   RNA_def_int(ot->srna,
               "start_frame",
-              INT_MIN, /* wm_obj_export_check uses this to set SFRA. */
+              INT_MIN, /* wm_obj_export_check uses this to set scene->r.sfra. */
               INT_MIN,
               INT_MAX,
               "Start Frame",
@@ -275,7 +275,7 @@ void WM_OT_obj_export(struct wmOperatorType *ot)
               INT_MAX);
   RNA_def_int(ot->srna,
               "end_frame",
-              INT_MAX, /* wm_obj_export_check uses this to set EFRA. */
+              INT_MAX, /* wm_obj_export_check uses this to set scene->r.efra. */
               INT_MIN,
               INT_MAX,
               "End Frame",