[patch] libstdc++/58038 libstdc++/60421 fix overflows in std::this_thread::sleep_for()

[Jonathan Wakely]

On 26/03/15 19:59 +0000, Jonathan Wakely wrote:
>We have a couple of bugs where durations with unsigned representations
>result in negative or huge time_t values, which result in not sleeping
>at all or sleeping for billions of years (or merely for decades if you
>have a 32-bit time_t).
>
>This change simply returns early for time points in the past or
>negative durations.
>
>Tested x86_64-linux, powerpc64le-linux, committed to trunk.

Also committed to the 4.9 branch.