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

1 files changed, 4 insertions, 4 deletions

diff --git a/source/blender/editors/gpencil/gpencil_interpolate.c b/source/blender/editors/gpencil/gpencil_interpolate.c
index 0039dbae674..e7a4f2fe2dc 100644
--- a/source/blender/editors/gpencil/gpencil_interpolate.c
+++ b/source/blender/editors/gpencil/gpencil_interpolate.c
@@ -483,10 +483,10 @@ static void gpencil_interpolate_set_points(bContext *C, tGPDinterpolate *tgpi)
     tgpil = MEM_callocN(sizeof(tGPDinterpolate_layer), "GPencil Interpolate Layer");
 
     tgpil->gpl = gpl;
-    bGPDframe *gpf = gpencil_get_previous_keyframe(gpl, CFRA);
+    bGPDframe *gpf = gpencil_get_previous_keyframe(gpl, scene->r.cfra);
     tgpil->prevFrame = BKE_gpencil_frame_duplicate(gpf, true);
 
-    gpf = gpencil_get_next_keyframe(gpl, CFRA);
+    gpf = gpencil_get_next_keyframe(gpl, scene->r.cfra);
     tgpil->nextFrame = BKE_gpencil_frame_duplicate(gpf, true);
 
     BLI_addtail(&tgpi->ilayers, tgpil);
@@ -750,7 +750,7 @@ static int gpencil_interpolate_invoke(bContext *C, wmOperator *op, const wmEvent
   tGPDinterpolate *tgpi = NULL;
 
   /* Cannot interpolate if not between 2 frames. */
-  int cfra = CFRA;
+  int cfra = scene->r.cfra;
   bGPDframe *gpf_prv = gpencil_get_previous_keyframe(gpl, cfra);
   bGPDframe *gpf_next = gpencil_get_next_keyframe(gpl, cfra);
   if (ELEM(NULL, gpf_prv, gpf_next)) {
@@ -1221,7 +1221,7 @@ static int gpencil_interpolate_seq_exec(bContext *C, wmOperator *op)
   GP_SpaceConversion gsc;
   gpencil_point_conversion_init(C, &gsc);
 
-  int cfra = CFRA;
+  int cfra = scene->r.cfra;
 
   GP_Interpolate_Settings *ipo_settings = &ts->gp_interpolate;
   const int step = RNA_int_get(op->ptr, "step");