[baseline][flatbuffers] backport fixes for Abseil and C++11 (#29974)

* [flatbuffers] backport fixes for Abseil and C++11

* Rebase and resolve conflicts

* Address review comments

ports/flatbuffers/fix-abseil-cxx14.patch

@@ -0,0 +1,13 @@
+diff --git a/include/flatbuffers/base.h b/include/flatbuffers/base.h
+index 86688cc6e40..219b6d308ac 100644
+--- a/include/flatbuffers/base.h
++++ b/include/flatbuffers/base.h
+@@ -233,7 +233,7 @@ namespace flatbuffers {
+       }
+       #define FLATBUFFERS_HAS_STRING_VIEW 1
+     // Check for absl::string_view
+-    #elif __has_include("absl/strings/string_view.h")
++    #elif __has_include("absl/strings/string_view.h") && (__cplusplus >= 201411)
+       #include "absl/strings/string_view.h"
+       namespace flatbuffers {
+         typedef absl::string_view string_view;

ports/flatbuffers/portfile.cmake

@@ -8,6 +8,7 @@ vcpkg_from_github(
     HEAD_REF master
     PATCHES
         fix-uwp-build.patch
+        fix-abseil-cxx14.patch
 )
 
 set(options "")

ports/flatbuffers/vcpkg.json

@@ -1,7 +1,7 @@
 {
   "name": "flatbuffers",
   "version": "23.1.21",
-  "port-version": 1,
+  "port-version": 2,
   "description": [
     "Memory Efficient Serialization Library",
     "FlatBuffers is an efficient cross platform serialization library for games and other memory constrained apps. It allows you to directly access serialized data without unpacking/parsing it first, while still having great forwards/backwards compatibility."

versions/baseline.json

@@ -2462,7 +2462,7 @@
     },
     "flatbuffers": {
       "baseline": "23.1.21",
-      "port-version": 1
+      "port-version": 2
     },
     "flecs": {
       "baseline": "3.1.4",

versions/f-/flatbuffers.json

@@ -1,5 +1,10 @@
 {
   "versions": [
+    {
+      "git-tree": "8079babd92cd3c1a80b224beb8f034b1a912a8b6",
+      "version": "23.1.21",
+      "port-version": 2
+    },
     {
       "git-tree": "c8dd8a45a079d9ec27da5352d1d61eb24ff94f5d",
       "version": "23.1.21",