[Bf-blender-cvs] [063f93d4a61] temp-T88822-gpu-thread-safe-index-builder: Added back optional include.

[Jeroen Bakker]

Commit: 063f93d4a615a83f04fc2397a734bce17c5a7f01
Author: Jeroen Bakker
Date:   Tue Jun 8 16:30:28 2021 +0200
Branches: temp-T88822-gpu-thread-safe-index-builder
https://developer.blender.org/rB063f93d4a615a83f04fc2397a734bce17c5a7f01

Added back optional include.

===================================================================

M	source/blender/draw/intern/draw_cache_extract_mesh.cc

===================================================================

diff --git a/source/blender/draw/intern/draw_cache_extract_mesh.cc b/source/blender/draw/intern/draw_cache_extract_mesh.cc
index 3d0d2adc310..7b2c0da4dd9 100644
--- a/source/blender/draw/intern/draw_cache_extract_mesh.cc
+++ b/source/blender/draw/intern/draw_cache_extract_mesh.cc
@@ -24,6 +24,8 @@
  */
 #include "MEM_guardedalloc.h"
 
+#include <optional>
+
 #include "atomic_ops.h"
 
 #include "DNA_mesh_types.h"