[flang] Remove C++ runtime dependency from Sleep extension

[DavidTruby]

The Sleep extension currently has a potential dependency on the C++ runtime. I
run into this dependency using libc++ on Linux. This patch uses the POSIX
sleep function or the Windows Sleep function instead to avoid this
dependency.

[llvmbot]

@llvm/pr-subscribers-flang-runtime

Author: David Truby (DavidTruby)

Changes

The Sleep extension currently has a potential dependency on the C++ runtime. I
run into this dependency using libc++ on Linux. This patch uses the POSIX
sleep function or the Windows Sleep function instead to avoid this
dependency.

---

Full diff: https://github.com/llvm/llvm-project/pull/84911.diff

1 Files Affected:

• (modified) flang/runtime/extensions.cpp (+5-1)

diff --git a/flang/runtime/extensions.cpp b/flang/runtime/extensions.cpp
index 3ac98000335d7d..fb11e792f613f5 100644
--- a/flang/runtime/extensions.cpp
+++ b/flang/runtime/extensions.cpp
@@ -135,7 +135,11 @@ void RTNAME(Sleep)(std::int64_t seconds) {
   if (seconds < 1) {
     return;
   }
-  std::this_thread::sleep_for(std::chrono::seconds(seconds));
+#if _WIN32
+  Sleep(seconds * 1000);
+#else
+  sleep(seconds);
+#endif
 }
 
 } // namespace Fortran::runtime

[tblah]

LGTM, thanks!

[github-actions]

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