QRandomGenerator: Rework the fallback seeding

qdeadlinetimer.cpp and qelapsedtimer_*.cpp are not part of the bootstrap
library. Instead of adding them there, just remove this entropy source
from bootstrapped builds (instead of just qmake).

To compensate, store all the bits instead of trying to combine them into
just one 32-bit word. We've got a few new sources from the stack and
libc, plus two more ELF auxvec values that the Linux kernel supplies
(inspired by OpenBSD's getentropy_linux.c, which is used in Bionic).

Task-number: QTBUG-61492
Change-Id: I1d5a585d4af842f9a66ffffd14c999ae8c44f46c
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

0 files changed, 0 insertions, 0 deletions