Fix T65671: Armature X-Mirror inconsistencies

Apparently the `rna_Armature_editbone_transform_update` function was incomplete because it didn't copy all mirrored transform values.

I also noticed that the same logic seen in `rna_Armature_editbone_transform_update` is also seen in `ED_armature_edit_transform_mirror_update`.
So the solution is expose and use that logic that updates a mirrored bone. Thus deduplicating and fixing T65671.

Reviewers: brecht, zeddb

Differential Revision: https://developer.blender.org/D5058

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/editors/include/ED_armature.h b/source/blender/editors/include/ED_armature.h
index 3eb277ad776..aca59e2868f 100644
--- a/source/blender/editors/include/ED_armature.h
+++ b/source/blender/editors/include/ED_armature.h
@@ -216,6 +216,9 @@ void ED_armature_ebone_to_mat4(EditBone *ebone, float mat[4][4]);
 void ED_armature_ebone_from_mat3(EditBone *ebone, float mat[3][3]);
 void ED_armature_ebone_from_mat4(EditBone *ebone, float mat[4][4]);
 
+void ED_armature_ebone_transform_mirror_update(struct bArmature *arm,
+                                               EditBone *ebo,
+                                               bool check_select);
 void ED_armature_edit_transform_mirror_update(struct Object *obedit);
 void ED_armature_origin_set(
     struct Main *bmain, struct Object *ob, const float cursor[3], int centermode, int around);