Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r234502:

After r217375, some startup objects under lib/csu are built in a special
way: first they are compiled to assembly, then some sed'ing is done on
the assembly, and lastly the assembly is compiled to an object file.

This last step is done using ${CC}, and not ${AS}, because when the
compiler is clang, it outputs directives that are too advanced for our
old gas. So we use clang's integrated assembler instead. (When the
compiler is gcc, it just calls gas, and nothing is different, except one
extra fork.)

However, in the .s to .o rules in lib/csu/$ARCH/Makefile, I still passed
CFLAGS to the compiler, instead of ACFLAGS, which are specifically for
compiling .s files.

In case you are using '-g' for debug info anywhere in your CFLAGS, it
causes the .s files to already contain debug information in the assembly
itself. In the next step, the .s files are also compiled using '-g',
and if the compiler is clang, it complains: "error: input can't have
.file dwarf directives when -g is used to generate dwarf debug info for
assembly code".

Fix this by using ${ACFLAGS} for compiling the .s files instead.

Reported by: jasone

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Apply a workaround for a binutils issue with the .note.ABI-tag section
generated from lib/csu/common/crtbrand.c (which ultimately ends up in
executables and shared libraries, via crt1.o, gcrt1.o or Scrt1.o).

For all arches except sparc, gcc emits the section directive for the
abitag struct in crtbrand.c with a PROGBITS type. However, newer
versions of binutils (after 2.16.90) require the section to be of NOTE
type, to guarantee that the .note.ABI-tag section correctly ends up in
the first page of the final executable.

Unfortunately, there is no clean way to tell gcc to use another section
type, so crtbrand.c (or the C files that include it) must be compiled in
multiple steps:

- Compile the .c file to a .s file.
- Edit the .s file to change the 'progbits' type to 'note', for the section
directive that defines the .note.ABI-tag section.
- Compile the .s file to an object file.

These steps are done in the invididual Makefiles for each applicable arch.

Reviewed by: kib

Use default WARNS setting (of 6) for lib/csu.

PR: bin/140089
Reviewed by: jmallett
Approved by: ed (co-mentor)

Properly support -fPIE by linking PIE binaries with specially-built
Scrt1.o instead of crt1.o, since the later is built as non-PIC.

Separate i386-elf crt1.c into the pure assembler part and C code,
supplying all data extracted by assembler stub as explicit parameters [1].
Hide and localize _start1 symbol used as an interface between asm and
C code.

In collaboration with: kan
Inspired by: PR i386/127387 [1]
Prodded and tested by: rdivacky [1]
MFC after: 3 weeks

Drop support for COPY, -c has been the default mode of install(1)
for a long time now.

Approved by: bde

Fixed CLEANFILES after bsd.lib.mk sweep.

SOBJS are not used here for a long time, and were just
pessimising the `install'.

Major cleanup of bsd.lib.mk.

Get rid of the INTERNALSTATICLIB knob and just use plain INTERNALLIB.
INTERNALLIB now means to build static library only and don't install
anything. Added a NOINSTALLLIB knob for libpam/modules. To not
build any library at all, just do not set LIB.

Revert the last change. The corresponding bsd.lib.mk changes were
already backed out.

Use the simpler NOMAN rather than NOMAN, NOPIC, NOPROFILE, INTERNALLIB.

Do not use __progname directly (except in [gs]etprogname(3)).
Also, make an internal _getprogname() that is used only inside
libc. For libc, getprogname(3) is a weak symbol in case a
function of the same name is defined in userland.

Sync with other platforms.

The instructions on doing something with src/lib/csu/powerpc.