Sync from upstream.

appveyor.yml

@@ -42,10 +42,6 @@ environment:
       CXXSTD: 11,14,1z
       ADDPATH: C:\cygwin64\bin;
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-    - TOOLSET: gcc
-      CXXSTD: 11,14,1z
-      ADDPATH: C:\mingw\bin;
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
     - TOOLSET: gcc
       CXXSTD: 11,14,1z
       ADDPATH: C:\mingw-w64\x86_64-6.3.0-posix-seh-rt_v5-rev1\mingw64\bin;

test/multiprecision_config.hpp

@@ -1,4 +1,4 @@
-// Copyright (c) 2018 Andrey Semashev
+// Copyright (c) 2018, 2024 Andrey Semashev
 //
 // Use, modification, and distribution is subject to the Boost Software
 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
@@ -8,25 +8,11 @@
 #define BOOST_INTEGER_TEST_MULTIPRECISION_CONFIG_HPP_INCLUDED_
 
 #include <boost/config.hpp>
-#include <boost/config/workaround.hpp>
 
-#if (defined(BOOST_MSVC) && (BOOST_MSVC < 1500)) || \
-    (defined(__clang_major__) && (__clang_major__ == 3) && (__clang_minor__ < 2)) || \
-    (defined(BOOST_GCC) && defined(BOOST_GCC_CXX11) && BOOST_GCC < 40800)
-#define DISABLE_MP_TESTS
-#endif
-
-// This list of checks matches those in Boost.Multiprecision, boost/multiprecision/detail/number_base.hpp,
-// as it no longer supports C++03 since 2021.
-#if !defined(DISABLE_MP_TESTS) && \
-    (\
-        defined(BOOST_NO_CXX11_RVALUE_REFERENCES) || defined(BOOST_NO_CXX11_TEMPLATE_ALIASES) || defined(BOOST_NO_CXX11_HDR_ARRAY) || defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS)\
-        || defined(BOOST_NO_CXX11_ALLOCATOR) || defined(BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX) || defined(BOOST_NO_CXX11_CONSTEXPR)\
-        || (defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS) || BOOST_WORKAROUND(__SUNPRO_CC, < 0x5140)) || defined(BOOST_NO_CXX11_REF_QUALIFIERS) || defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)\
-        || defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) || defined(BOOST_NO_CXX11_USER_DEFINED_LITERALS) || defined(BOOST_NO_CXX11_THREAD_LOCAL)\
-        || defined(BOOST_NO_CXX11_DECLTYPE) || defined(BOOST_NO_CXX11_STATIC_ASSERT) || defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)\
-        || defined(BOOST_NO_CXX11_NOEXCEPT) || defined(BOOST_NO_CXX11_REF_QUALIFIERS)\
-    )
+// Boost.Multiprecision requires a number of C++11 features, see boost/multiprecision/detail/check_cpp11_config.hpp.
+// Also, Boost.Multiprecision internally uses Boost.Math, which requires C++14 and a recent enough MSVC, see boost/math/tools/config.hpp.
+#if (BOOST_CXX_VERSION < 201402) || \
+    (defined(_MSC_VER) && (_MSC_VER <= 1900))
 #define DISABLE_MP_TESTS
 #endif