QProcess/Unix: move strerror() up from child to parent

In theory, there's nothing wrong with having it in the child process. In
practice, we've found that strerror/malloc can hang: if an application-
wide lock was held by another thread before fork(), the child process
could wait forever for an unlocking that will not happen (no threads
running). See https://sourceware.org/bugzilla/show_bug.cgi?id=19431

As an added bonus, we now use qt_error_string(), which may produce
slightly different text from strerror.

[ChangeLog][QtCore][QProcess] Added a workaround for a rare race-
condition bug in some C libraries that caused the child process started
by QProcess to hang after trying to launch a non-existent executable or
change to a non-existent directory.

Task-number: QTBUG-61634
Change-Id: I1eba2b016de74620bfc8fffd14cbce4b9f9af69b
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>

0 files changed, 0 insertions, 0 deletions