Revert "[SystemZ][ZOS] Porting the time functions within libc++ to z/OS"

This reverts commit 173b51169b. That commit was applied incorrectly,
and undid previous changes. That was clearly not intended.

libcxx/include/CMakeLists.txt

@@ -179,29 +179,6 @@ set(files
   wctype.h
   )
 
-if(LIBCXX_INSTALL_SUPPORT_HEADERS)
-  set(files
-    ${files}
-    support/android/locale_bionic.h
-    support/fuchsia/xlocale.h
-    support/ibm/limits.h
-    support/ibm/locale_mgmt_aix.h
-    support/ibm/nanosleep.h
-    support/ibm/support.h
-    support/ibm/xlocale.h
-    support/musl/xlocale.h
-    support/newlib/xlocale.h
-    support/solaris/floatingpoint.h
-    support/solaris/wchar.h
-    support/solaris/xlocale.h
-    support/win32/limits_msvc_win32.h
-    support/win32/locale_win32.h
-    support/xlocale/__nop_locale_mgmt.h
-    support/xlocale/__posix_l_fallback.h
-    support/xlocale/__strtonum_fallback.h
-    )
-endif()
-
 configure_file("__config_site.in"
                "${LIBCXX_BINARY_DIR}/__config_site"
                @ONLY)

libcxx/include/__threading_support

@@ -16,10 +16,6 @@
 #include <iosfwd>
 #include <errno.h>
 
-#ifdef __MVS__
-#include <support/ibm/nanosleep.h>
-#endif
-
 #ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
 #pragma GCC system_header
 #endif

libcxx/include/support/ibm/nanosleep.h

@@ -1,38 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_SUPPORT_IBM_NANOSLEEP_H
-#define _LIBCPP_SUPPORT_IBM_NANOSLEEP_H
-
-#include <unistd.h>
-
-inline int nanosleep(const struct timespec* req, struct timespec* rem)
-{
-   // The nanosleep() function is not available on z/OS. Therefore, we will call
-   // sleep() to sleep for whole seconds and usleep() to sleep for any remaining
-   // fraction of a second. Any remaining nanoseconds will round up to the next
-   // microsecond.
-
-   useconds_t __micro_sec = (rem->tv_nsec + 999) / 1000;
-   if (__micro_sec > 999999)
-   {
-     ++rem->tv_sec;
-     __micro_sec -= 1000000;
-   }
-   while (rem->tv_sec)
-      rem->tv_sec = sleep(rem->tv_sec);
-   if (__micro_sec) {
-     rem->tv_nsec = __micro_sec * 1000;
-     return usleep(__micro_sec);
-   }
-   rem->tv_nsec = 0;
-   return 0;
-}
-
-#endif // _LIBCPP_SUPPORT_IBM_NANOSLEEP_H

libcxx/src/filesystem/filesystem_common.h

@@ -198,8 +198,7 @@ private:
 using chrono::duration;
 using chrono::duration_cast;
 
-using TimeSpec = struct timespec;
-using TimeVal = struct timeval;
+using TimeSpec = timespec;
 using StatT = struct stat;
 
 template <class FileTimeT, class TimeT,
@@ -382,38 +381,26 @@ public:
 using fs_time = time_util<file_time_type, time_t, TimeSpec>;
 
 #if defined(__APPLE__)
-inline TimeSpec extract_mtime(StatT const& st) { return st.st_mtimespec; }
-inline TimeSpec extract_atime(StatT const& st) { return st.st_atimespec; }
-#elif defined(__MVS__)
-inline TimeSpec extract_mtime(StatT const& st) {
-  TimeSpec TS = {st.st_mtime, 0};
-  return TS;
-}
-inline TimeSpec extract_atime(StatT const& st) {
-  TimeSpec TS = {st.st_atime, 0};
-  return TS;
-}
+TimeSpec extract_mtime(StatT const& st) { return st.st_mtimespec; }
+TimeSpec extract_atime(StatT const& st) { return st.st_atimespec; }
 #else
-inline TimeSpec extract_mtime(StatT const& st) { return st.st_mtim; }
-inline TimeSpec extract_atime(StatT const& st) { return st.st_atim; }
+TimeSpec extract_mtime(StatT const& st) { return st.st_mtim; }
+TimeSpec extract_atime(StatT const& st) { return st.st_atim; }
 #endif
 
-inline TimeVal make_timeval(TimeSpec const& ts) {
+// allow the utimes implementation to compile even it we're not going
+// to use it.
+
+bool posix_utimes(const path& p, std::array<TimeSpec, 2> const& TS,
+                  error_code& ec) {
   using namespace chrono;
   auto Convert = [](long nsec) {
-    using int_type = decltype(std::declval<TimeVal>().tv_usec);
+    using int_type = decltype(std::declval< ::timeval>().tv_usec);
     auto dur = duration_cast<microseconds>(nanoseconds(nsec)).count();
     return static_cast<int_type>(dur);
   };
-  TimeVal TV = {};
-  TV.tv_sec = ts.tv_sec;
-  TV.tv_usec = Convert(ts.tv_nsec);
-  return TV;
-}
-
-inline bool posix_utimes(const path& p, std::array<TimeSpec, 2> const& TS,
-                  error_code& ec) {
-  TimeVal ConvertedTS[2] = {make_timeval(TS[0]), make_timeval(TS[1])};
+  struct ::timeval ConvertedTS[2] = {{TS[0].tv_sec, Convert(TS[0].tv_nsec)},
+                                     {TS[1].tv_sec, Convert(TS[1].tv_nsec)}};
   if (::utimes(p.c_str(), ConvertedTS) == -1) {
     ec = capture_errno();
     return true;