From 49444a529bd52c307d574f82b23a35e17e1a0f17 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 8 Jul 2020 18:18:35 +0400
Subject: [PATCH] Force using of std::optional.

---
 webrtc_build.diff       | 17 +++++++++++++----
 webrtc_third_party.diff | 13 +++++++++++++
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/webrtc_build.diff b/webrtc_build.diff
index f483060..adda665 100644
--- a/webrtc_build.diff
+++ b/webrtc_build.diff
@@ -12,7 +12,7 @@ index 5ced4596f..db1b27cb2 100644
        (is_linux &&
         (!is_chromeos || default_toolchain != "//build/toolchain/cros:target"))
 diff --git a/config/compiler/BUILD.gn b/config/compiler/BUILD.gn
-index 3d5e4dede..bd6a7ddc4 100644
+index 3d5e4dede..17b3bcfd0 100644
 --- a/config/compiler/BUILD.gn
 +++ b/config/compiler/BUILD.gn
 @@ -535,7 +535,7 @@ config("compiler") {
@@ -24,7 +24,16 @@ index 3d5e4dede..bd6a7ddc4 100644
      }
    } else if (!is_win && !is_nacl) {
      if (target_os == "android") {
-@@ -1379,6 +1379,8 @@ config("default_warnings") {
+@@ -554,6 +554,8 @@ config("compiler") {
+     } else {
+       cflags_cc += [ "-std=c++14" ]
+     }
++  } else if (is_win) {
++    cflags_cc += [ "/std:c++17" ]
+   }
+ 
+   if (is_mac) {
+@@ -1379,6 +1381,8 @@ config("default_warnings") {
  
        "/wd4715",  # 'function' : not all control paths return a value'
                    # MSVC does not analyze switch (enum) for completeness.
@@ -33,7 +42,7 @@ index 3d5e4dede..bd6a7ddc4 100644
      ]
  
      cflags_cc += [
-@@ -1488,7 +1490,7 @@ config("default_warnings") {
+@@ -1488,7 +1492,7 @@ config("default_warnings") {
          cflags += [ "-Wno-nonportable-include-path" ]
        }
  
@@ -42,7 +51,7 @@ index 3d5e4dede..bd6a7ddc4 100644
          # Flags NaCl (Clang 3.7) and Xcode 9.2 (Clang clang-900.0.39.2) do not
          # recognize.
          cflags += [
-@@ -1528,6 +1530,24 @@ config("default_warnings") {
+@@ -1528,6 +1532,24 @@ config("default_warnings") {
          ]
        }
      }
diff --git a/webrtc_third_party.diff b/webrtc_third_party.diff
index 617ec75..537c086 100644
--- a/webrtc_third_party.diff
+++ b/webrtc_third_party.diff
@@ -12,6 +12,19 @@ index a62632e2c3f..ea2a9325a9c 100644
  }
  
  config("libjpeg_turbo_config") {
+diff --git a/abseil-cpp/absl/types/optional.h b/abseil-cpp/absl/types/optional.h
+index 61540cfdb26..3249d1b90d3 100644
+--- a/abseil-cpp/absl/types/optional.h
++++ b/abseil-cpp/absl/types/optional.h
+@@ -54,6 +54,8 @@ ABSL_NAMESPACE_END
+ 
+ #else  // ABSL_USES_STD_OPTIONAL
+ 
++#error "Build with non-std optional is not supported."
++
+ #include <cassert>
+ #include <functional>
+ #include <initializer_list>
 diff --git a/libjpeg.gni b/libjpeg.gni
 index 049348b79bd..039385c9739 100644
 --- a/libjpeg.gni