Regenerate artifacts, deprecate vs2017/vs2019, elevate from c++11 to …

…c++20.

build.cmd

@@ -69,7 +69,7 @@ IF %ERRORLEVEL% NEQ 0 (
   exit /b 1
 )
 call cd /d "%path_base%\%~1\builds\msvc\%proj_version%"
-call "%msbuild_exe%" %msbuild_args% %~1.sln
+call "%msbuild_exe%" %msbuild_args% %~1.sln /p:PreBuildEventUseInBuild=false /p:PostBuildEventUseInBuild=false
 IF %ERRORLEVEL% NEQ 0 (
   call :failure "%msbuild_exe% %msbuild_args% %~1.sln failed."
   exit /b 1
@@ -86,7 +86,7 @@ IF %ERRORLEVEL% NEQ 0 (
   exit /b 1
 )
 call cd /d "%path_base%\%~1\builds\msvc\%proj_version%"
-call "%msbuild_exe%" %msbuild_args% /target:%~1:Rebuild %~1.sln
+call "%msbuild_exe%" %msbuild_args% /target:%~1:Rebuild %~1.sln /p:PreBuildEventUseInBuild=false /p:PostBuildEventUseInBuild=false
 IF %ERRORLEVEL% NEQ 0 (
   call :failure "%msbuild_exe% %msbuild_args% /target:%~1:Rebuild %~1.sln"
   exit /b 1

builds/cmake/CMakeLists.txt

@@ -34,7 +34,7 @@ else ()
   set( VERSION "${PACKAGE_VERSION}" )
 endif ()
 
-set( CMAKE_CXX_STANDARD 11 )
+set( CMAKE_CXX_STANDARD 20 )
 set( CMAKE_CXX_STANDARD_REQUIRED ON )
 
 # Add compiler options
@@ -60,6 +60,9 @@ add_compile_options( "-Wno-missing-braces" )
 # Ignore comments within comments or commenting of backslash extended lines.
 add_compile_options( "-Wno-comment" )
 
+# Suppress warning for copy of implicitly generated copy constructor.
+add_compile_options( "-Wno-deprecated-copy" )
+
 # Conflict in stdlib under clang.
 if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
     add_compile_options( "-Wno-mismatched-tags" )