From cc6610f42c4d4a6fa2494eef5fe93942075bd340 Mon Sep 17 00:00:00 2001
From: Leonid Yuriev <leo@yuriev.ru>
Date: Thu, 24 Jun 2021 15:41:54 +0300
Subject: [PATCH] mdbx: more/refine C++ crutches for mad MSVC compiler.

---
 CMakeLists.txt | 12 +++++++++++-
 mdbx.h++       | 14 ++++++++------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0aad9f88..e74432b0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -539,6 +539,13 @@ else()
   message(STATUS "Use C${MDBX_C_STANDARD} for libmdbx but C++ portion is disabled")
 endif()
 
+if(SUBPROJECT AND MSVC)
+  if(MSVC_VERSION LESS 1900)
+    message(FATAL_ERROR "At least \"Microsoft C/C++ Compiler\" version 19.0.24234.1 (Visual Studio 2015 Update 3) is required.")
+  endif()
+  add_compile_options("/utf-8")
+endif()
+
 macro(target_setup_options TARGET)
   if(DEFINED INTERPROCEDURAL_OPTIMIZATION)
     set_target_properties(${TARGET} PROPERTIES
@@ -549,6 +556,9 @@ macro(target_setup_options TARGET)
   if(MDBX_BUILD_CXX)
     set_target_properties(${TARGET} PROPERTIES
       CXX_STANDARD ${MDBX_CXX_STANDARD} CXX_STANDARD_REQUIRED ON)
+    if(MSVC AND NOT MSVC_VERSION LESS 1910)
+      target_compile_options(${TARGET} INTERFACE "/Zc:__cplusplus")
+    endif()
   endif()
   if(CC_HAS_FASTMATH)
     target_compile_options(${TARGET} PRIVATE "-ffast-math")
@@ -557,7 +567,7 @@ macro(target_setup_options TARGET)
     target_compile_options(${TARGET} PRIVATE "-fvisibility=hidden")
   endif()
   if(BUILD_FOR_NATIVE_CPU AND CC_HAS_ARCH_NATIVE)
-    target_compile_options(${TARGET} PUBLIC "-march=native")
+    target_compile_options(${TARGET} PRIVATE "-march=native")
   endif()
 endmacro()
 
diff --git a/mdbx.h++ b/mdbx.h++
index fce43a41..c70e6fd4 100644
--- a/mdbx.h++
+++ b/mdbx.h++
@@ -14,12 +14,14 @@
 
 #pragma once
 
-#if (!defined(__cplusplus) || __cplusplus < 201103L) &&                        \
-    !(defined(                                                                 \
-          _MSC_VER) /* MSVC is mad and don't define __cplusplus properly */    \
-      && _MSC_VER == 1900)
-#error "C++11 or better is required"
-#endif
+#if !defined(__cplusplus) || __cplusplus < 201103L
+#if !defined(_MSC_VER) || _MSC_VER < 1900
+#error "C++11 compiler or better is required"
+#elif _MSC_VER >= 1910
+#error                                                                         \
+    "Please add ` /Zc:__cplusplus` to MSVC compiler options to enforce it conform ISO C++"
+#endif /* MSVC is mad and don't define __cplusplus properly */
+#endif /* __cplusplus < 201103L */
 
 #if (defined(_WIN32) || defined(_WIN64)) && MDBX_WITHOUT_MSVC_CRT
 #error                                                                         \