+static void apply_full_skeleton_pose( struct skeleton *sk, player_pose *pose,
+ m4x3f *final_mtx );
+static void lerp_player_pose( player_pose *pose0, player_pose *pose1, f32 t,
+ player_pose *posed );
+static void player_mirror_pose( mdl_keyframe pose[32],
+ mdl_keyframe mirrored[32] );
+static void player__observe_system( enum player_subsystem id );