Create a new pipe in the child process.
In a normal desktop LibreOffice each fork() will be followed quickly
by an exec(), so the FD_CLOEXEC would be enough for that. In
LibreOfficeKit-based software that uses the preinit mechanism, though,
the intent is that one can fork child processes without exec().
This solution uses pthread_atfork(). Another way would be to add
suitable public API callable from the LibreOfficeKit client
initialisation code in desktop/source/lib/init.cxx to explicitly close
and reopen the wakeup pipe in the default SvpSalInstance.
Change-Id: I03fad4ce4adf14c16cb0f537b3baab58fba38922
Reviewed-on: https://gerrit.libreoffice.org/24256
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Michael Meeks <michael.meeks@collabora.com>
dbced8e858