[RESEND PATCH] Makeconfig: Set pie-ccflag to -fPIE by default

[Florian Weimer]

* Wilco Dijkstra via Libc-alpha:

> However this leads to the question is why aren't all symbols marked as
> hidden in the static PIE build? Ie. are there any symbols that must be
> shared with a DSO loaded by a dl_open?

The static main executable does not have a dynamic symbol table, so such
sharing cannot happen (except through function pointers being passed
around, but symbol visibility of course does not matter there).

Thanks,
Florian