[libcxx] Define LIBCPP_HAS_TIMESPEC_GET for MSVC configurations

[mstorsjo]

Summary

This define was out of sync with the corresponding define in tests, it
was added inconsistently in 171c77b7dad4a050aca23ff7ca1b75f87560fefb.

Modern MSVC environments do have these typedefs and functions.

libcxx/include/__config

 #        define _LIBCPP_HAS_ALIGNED_ALLOC
 #        define _LIBCPP_HAS_TIMESPEC_GET
 #      endif
 #    else // defined(_LIBCPP_HAS_MUSL_LIBC)
 #      define _LIBCPP_HAS_ALIGNED_ALLOC
 #      define _LIBCPP_HAS_QUICK_EXIT
 #      define _LIBCPP_HAS_TIMESPEC_GET
 #    endif
+#  elif defined(_LIBCPP_MSVCRT)
+     // Using Microsoft's C Runtime library, not MinGW
+#    define _LIBCPP_HAS_TIMESPEC_GET
 #  elif defined(__APPLE__)
      // timespec_get and aligned_alloc were introduced in macOS 10.15 and
      // aligned releases
 #    if ((defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101500) || \
          (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ >= 130000) || \
          (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ >= 130000) || \
          (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ >= 60000))
 #      define _LIBCPP_HAS_ALIGNED_ALLOC

libcxx/test/libcxx/language.support/has_timespec_get.compile.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14
 
-// XFAIL: LIBCXX-WINDOWS-FIXME
-
 // Make sure TEST_HAS_TIMESPEC_GET (defined by the test suite) and
 // _LIBCPP_HAS_TIMESPEC_GET (defined by libc++) stay in sync.
 
 #include <__config>
 #include "test_macros.h"
 
 #if defined(TEST_HAS_TIMESPEC_GET) != defined(_LIBCPP_HAS_TIMESPEC_GET)
 #   error "TEST_HAS_TIMESPEC_GET and _LIBCPP_HAS_TIMESPEC_GET are out of sync"
 #endif

libcxx/test/std/language.support/support.runtime/ctime.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // test <ctime>
 
-// XFAIL: LIBCXX-WINDOWS-FIXME
-
 #include <ctime>
 #include <type_traits>
 #include "test_macros.h"
 
 #ifndef NULL
 #error NULL not defined
 #endif
 

libcxx/test/std/utilities/time/date.time/ctime.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
-// XFAIL: LIBCXX-WINDOWS-FIXME
-
 #include <ctime>
 #include <type_traits>
 
 #include "test_macros.h"
 
 #ifndef NULL
 #error NULL not defined
 #endif