get_cycles passes the pthread handle to pthread_getcpuclockid, which glibc
answers with an error for a thread that has already exited -- the else branch
below returns the last known value for exactly that case. bionic instead looks
the handle up in its list of live threads and aborts the process when it is not
there.
m_thread is never cleared when a thread ends and the performance overlay samples
every PPU, SPU and RSX thread on a timer, so one finished thread is enough to
take the emulator down with it. Latent here rather than absent: it needs the
overlay on and a thread to have gone.
Record the kernel tid at initialize and build the per-thread clock id from it
the way bionic does once its own lookup succeeds, so clock_gettime simply fails
for a dead thread, which is what the surrounding code already expects. Cleared
at finalize so a thread stops being sampled before it goes away. Other platforms
keep the original path.
Found and fixed by Zulux91 in PS3Native.
