Sponsored by:	Netflix

Also need to make some small tweaks to the Makefiles to use += rather
than = due to small shift in include file order.

Sponsored by: Netflix

not page aligned. To do this, use the ld script gnu ld installs on my
system.

This is imperfect: LDFLAGS_BIN and LD_FLAGS_BIN describe different
things. The loader script could be better named and take into account
other architectures. And having two different mechanisms to do
basically the same thing needs study. However, it's blocking forward
progress on lld, so I'll work in parallel to sort these out.

Differential Revision: https://reviews.freebsd.org/D7409
Reviewed by: emaste

Sponsored by:	EMC / Isilon Storage Division

1. 50+% of NO_PIE use is fixed by adding -fPIC to INTERNALLIB and other
   build-only utility libraries.
2. Another 40% is fixed by generating _pic.a variants of various libraries.
3. Some of the NO_PIE use is a bit absurd as it is disabling PIE (and ASLR)
   where it never would work anyhow, such as csu or loader. This suggests
   there may be better ways of adding support to the tree. Many of these
   cases can be fixed such that -fPIE will work but there is really no
   reason to have it in those cases.
4. Some of the uses are working around hacks done to some Makefiles that are
   really building libraries but have been using bsd.prog.mk because the code
   is cleaner. Had they been using bsd.lib.mk then NO_PIE would not have
   been needed.

We likely do want to enable PIE by default (opt-out) for non-tree consumers
(such as ports). For in-tree though we probably want to only enable PIE
(opt-in) for common attack targets such as remote service daemons and setuid
utilities. This is also a great performance compromise since ASLR is expected
to reduce performance. As such it does not make sense to enable it in all
utilities such as ls(1) that have little benefit to having it enabled.

Reported by:	kib

This is currently an opt-in build flag. Once ASLR support is ready and stable
it should changed to opt-out and be enabled by default along with ASLR.

Each application Makefile uses opt-out to ensure that ASLR will be enabled by
default in new directories when the system is compiled with PIE/ASLR. [2]

Mark known build failures as NO_PIE for now.

The only known runtime failure was rtld.

[1] http://www.bsdcan.org/2014/schedule/events/452.en.html
Submitted by:		Shawn Webb <lattera@gmail.com>
Discussed between:	des@ and Shawn Webb [2]

and finish the job. ncurses is now the only Makefile in the tree that
uses it since it wasn't a simple mechanical change, and will be
addressed in a future commit.

Place the arguments at a fixed offset of 0x800 withing the argument area
(of size 0x1000).  Allow variable size extended arguments first of which
should be a size of the extended arguments (including the size
parameter).

Consolidate all related definitions in a new i386/common/bootargs.h header.

Many thanks to jhb and bde for their guidance and reviews.

Reviewed by:	jhb, bde
Approved by:	jhb
MFC after:	1 month

get rid of testing explicitly for clang (using ${CC:T:Mclang}) in
individual Makefiles.

Instead, use the following extra macros, for use with clang:
- NO_WERROR.clang       (disables -Werror)
- NO_WCAST_ALIGN.clang  (disables -Wcast-align)
- NO_WFORMAT.clang	(disables -Wformat and friends)
- CLANG_NO_IAS		(disables integrated assembler)
- CLANG_OPT_SMALL	(adds flags for extra small size optimizations)

As a side effect, this enables setting CC/CXX/CPP in src.conf instead of
make.conf!  For clang, use the following:

CC=clang
CXX=clang++
CPP=clang-cpp

MFC after:	2 weeks

This contains many improvements, primarily better C++ support, an
integrated assembler for x86 and support for -pg.