MFS r352754: Add WITH_PIE knob to build Position Independent Executables

MFS r352754: Add WITH_PIE knob to build Position Independent Executables

MFC r344179: Add WITH_PIE knob to build Position Independent Executables

Building binaries as PIE allows the executable itself to be loaded at a
random address when ASLR is enabled (not just its shared libraries).

With this change PIE objects have a .pieo extension and INTERNALLIB
libraries libXXX_pie.a.

MK_PIE is disabled for some kerberos5 tools, Clang, and Subversion, as
they explicitly reference .a libraries in their Makefiles.  These can
be addressed on an individual basis later.  MK_PIE is also disabled for
rtld-elf because it is already position-independent using bespoke
Makefile rules.

Currently only dynamically linked binaries will be built as PIE.

MFC r344181: Fix Makefile conditional after r344179

MFC r344182: Use make's :tl instead of checking "no" and "NO"

MFC r344189: Fixup bsd.prog.mk after r344182

MFC r344211: wlandebug: disable PIE to fix build failure

libifconfig is built as a static-only PRIVATELIB (and there is no _pie.a
version) so disable PIE in libifconfig's consumer.

r345489: Fix GNU objdump build under WITH_PIE

Explicitly specified bare .a libraries need ${PIE_SUFFIX}.

r345490: Apply WITH_PIE changes to other binutils components

Followon to r345489, explicitly specified bare .a libraries need
${PIE_SUFFIX} (although these still built).

r345778: Fix gdb/kgdb build under WITH_PIE

Explicitly specified bare .a libraries need ${PIE_SUFFIX}.

Approved by:	re (gjb)
Sponsored by:	The FreeBSD Foundation