install.pike: Update CXX smartlink path to installed path as well.
release number bumped to 884 by export.pike
release number bumped to 885 by export.pike
Stdio.File: More race fixes in connect() [bug 7293].

It seems the backend on Linux sometimes may trigger before the connect(2)
is done with POLLIN and a state where read(2) fails with ENOTCONN.

Reduce the race condition by inhibiting backend callbacks on the
fd during connect(2).
release number bumped to 886 by export.pike
release number bumped to 887 by export.pike