From d2b74e4da5d04fe970689994a36d0678205e53ce Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=9B=D0=B5=D0=BE=D0=BD=D0=B8=D0=B4=20=D0=AE=D1=80=D1=8C?=
 =?UTF-8?q?=D0=B5=D0=B2=20=28Leonid=20Yuriev=29?= <leo@yuriev.ru>
Date: Tue, 8 Oct 2024 23:08:52 +0300
Subject: [PATCH] =?UTF-8?q?mdbx-cmake:=20=D0=B2=D0=BA=D0=BB=D1=8E=D1=87?=
 =?UTF-8?q?=D0=B5=D0=BD=D0=B8=D0=B5=20=D1=81=D1=82=D0=B0=D0=BD=D0=B4=D0=B0?=
 =?UTF-8?q?=D1=80=D1=82=D0=B0=20`C23`.?=
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---
 CMakeLists.txt       |  8 ++++++--
 cmake/compiler.cmake | 10 +++++++---
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 605f2248..59dcada5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -450,7 +450,6 @@ if(MDBX_MANAGE_BUILD_FLAGS)
   setup_compile_flags()
 endif()
 
-list(FIND CMAKE_C_COMPILE_FEATURES c_std_11 HAS_C11)
 list(FIND CMAKE_CXX_COMPILE_FEATURES cxx_std_11 HAS_CXX11)
 list(FIND CMAKE_CXX_COMPILE_FEATURES cxx_std_14 HAS_CXX14)
 list(FIND CMAKE_CXX_COMPILE_FEATURES cxx_std_17 HAS_CXX17)
@@ -481,6 +480,9 @@ if(NOT DEFINED MDBX_CXX_STANDARD)
     set(MDBX_CXX_STANDARD 98)
   endif()
 endif()
+
+list(FIND CMAKE_C_COMPILE_FEATURES c_std_11 HAS_C11)
+list(FIND CMAKE_C_COMPILE_FEATURES c_std_23 HAS_C23)
 if(NOT DEFINED MDBX_C_STANDARD)
   # MSVC >= 19.28 (Microsoft Visual Studio 16.8) is mad!
   #               It unable process Windows SDK headers in the C11 mode!
@@ -488,6 +490,8 @@ if(NOT DEFINED MDBX_C_STANDARD)
     set(MDBX_C_STANDARD 99)
     set(C_FALLBACK_11 OFF)
     set(C_FALLBACK_GNU11 OFF)
+  elseif(NOT HAS_C23 LESS 0)
+    set(MDBX_C_STANDARD 23)
   elseif(HAS_C11 LESS 0 AND NOT C_FALLBACK_GNU11 AND NOT C_FALLBACK_11)
     set(MDBX_C_STANDARD 99)
   else()
@@ -800,7 +804,7 @@ macro(target_setup_options TARGET)
     set_target_properties(${TARGET} PROPERTIES
       INTERPROCEDURAL_OPTIMIZATION $<BOOL:${INTERPROCEDURAL_OPTIMIZATION}>)
   endif()
-  if(NOT C_FALLBACK_GNU11 AND NOT C_FALLBACK_11)
+  if(NOT MDBX_C_STANDARD EQUAL 11 OR (NOT C_FALLBACK_GNU11 AND NOT C_FALLBACK_11))
     set_target_properties(${TARGET} PROPERTIES
       C_STANDARD ${MDBX_C_STANDARD} C_STANDARD_REQUIRED ON)
   endif()
diff --git a/cmake/compiler.cmake b/cmake/compiler.cmake
index bd50b9d7..a6c7f618 100644
--- a/cmake/compiler.cmake
+++ b/cmake/compiler.cmake
@@ -384,9 +384,13 @@ endif()
 if(CMAKE_CXX_COMPILER_LOADED)
   list(FIND CMAKE_CXX_COMPILE_FEATURES cxx_std_11 HAS_CXX11)
   if(HAS_CXX11 LESS 0)
-    check_cxx_compiler_flag("-std=gnu++11" CXX_FALLBACK_GNU11)
-    if(NOT CXX_FALLBACK_GNU11)
-      check_cxx_compiler_flag("-std=c++11" CXX_FALLBACK_11)
+    if (MSVC)
+      check_cxx_compiler_flag("/std:c++11" CXX_FALLBACK_11)
+    else()
+      check_cxx_compiler_flag("-std=gnu++11" CXX_FALLBACK_GNU11)
+      if(NOT CXX_FALLBACK_GNU11)
+        check_cxx_compiler_flag("-std=c++11" CXX_FALLBACK_11)
+      endif()
     endif()
   endif()
 endif()