[gcc(refs/users/aoliva/heads/testme)] libstdc++: 60241.cc: tolerate slightly shorter aggregate sleep

[Alexandre Oliva]

https://gcc.gnu.org/g:4ff3b788e20d6ff5d1e9830ecc27cc82ee90879a

commit 4ff3b788e20d6ff5d1e9830ecc27cc82ee90879a
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Mon Jun 20 20:44:10 2022 -0300

    libstdc++: 60241.cc: tolerate slightly shorter aggregate sleep
    
    On rtems under qemu, the frequently-interrupted nanosleep ends up
    sleeping shorter than expected, by a margin of less than 0,3%.
    
    I figured failing the library test over a system (emulator?) bug is
    undesirable, so I put in some tolerance for the drift.
    
    
    for  libstdc++-v3/ChangeLog
    
            * testsuite/30_threads/this_thread/60421.cc: Tolerate a
            slightly early wakeup.

Diff:
---
 libstdc++-v3/testsuite/30_threads/this_thread/60421.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/testsuite/30_threads/this_thread/60421.cc b/libstdc++-v3/testsuite/30_threads/this_thread/60421.cc
index 12dbeba1cc4..f3a5af453c4 100644
--- a/libstdc++-v3/testsuite/30_threads/this_thread/60421.cc
+++ b/libstdc++-v3/testsuite/30_threads/this_thread/60421.cc
@@ -51,9 +51,10 @@ test02()
   std::thread t([&result, &sleeping] {
     auto start = std::chrono::system_clock::now();
     auto time = std::chrono::seconds(3);
+    auto tolerance = std::chrono::milliseconds(10);
     sleeping = true;
     std::this_thread::sleep_for(time);
-    result = std::chrono::system_clock::now() >= (start + time);
+    result = std::chrono::system_clock::now() + tolerance >= (start + time);
     sleeping = false;
   });
   while (!sleeping)