QBenchlib/Perf: open the perffd with PERF_FLAG_FD_CLOEXEC

This flag was introduced in the Linux kernel version 3.14. Trying to use
perf_event_open() now with a kernel older than that will cause EINVAL
errors, but 3.14 is from 2014, so most likely old enough for all of
Qt 6.

For that, I updated the copied header from v6.0.

Pick-to: 6.4
Change-Id: I3c79b7e08fa346988dfefffd171f895201ceb4f4
Reviewed-by: Fabian Kosmale <[email protected]>

0 files changed, 0 insertions, 0 deletions