Build: Perform CMake check_cxx_source_compiles checks using the same C++ standard as used in the project

CMakeLists.txt

@@ -21,6 +21,7 @@ project(TrinityCore)
 cmake_policy(SET CMP0005 NEW)
 cmake_policy(SET CMP0043 NEW) # Ignore COMPILE_DEFINITIONS_<Config> properties
 cmake_policy(SET CMP0054 NEW) # Only interpret if() arguments as variables or keywords when unquoted - prevents intepreting if(SOME_STRING_VARIABLE MATCHES "MSVC") as if(SOME_STRING_VARIABLE MATCHES "1")
+cmake_policy(SET CMP0067 NEW) # Honor language standard in try_compile() source-file signature
 cmake_policy(SET CMP0074 NEW) # find_package() uses <PackageName>_ROOT variables
 
 if(POLICY CMP0144)

cmake/macros/ConfigureBaseTargets.cmake

@@ -13,14 +13,11 @@ add_library(trinity-compile-option-interface INTERFACE)
 
 # Use -std=c++11 instead of -std=gnu++11
 set(CMAKE_CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD 20)
 
 # An interface library to make the target features available to other targets
 add_library(trinity-feature-interface INTERFACE)
 
-target_compile_features(trinity-feature-interface
-  INTERFACE
-    cxx_std_20)
-
 # An interface library to make the warnings level available to other targets
 # This interface taget is set-up through the platform specific script
 add_library(trinity-warning-interface INTERFACE)