This is a direct port of HardenedBSD's
hardened/10-stable/master's Position-Independent Executable (PIE)
support. This code is only applicable to base and does not get applied
to ports.
The only change made was to enable PIE for amd64 and i386 by default.
All other architectures have it disabled (due to lack of hardware with
which to test).
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>