MFC r314556-r314558

r314556:
Correct MDSRCS use in <arch>/string/Makefile.inc.

- Remove .c files which duplicate entries in MISRCS.
- Use the same, less merge conflict prone style in all cases.
- Use MDSRCS for mips (.c and .S files both ended up in SRCS).
- Remove pointless sparc64 Makefile.inc.
- Remove uninformative foreign VCS ID entries.

Reviewed by: emaste, imp, jhb
MFC after: 1 week
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D9841

r314557:
Correct an misunderstanding of MDSRCS.

MDSRCS it intended to allow assembly versions of funtions with C
implementations listed in MISRCS. The selection of the correct
machdep_ldis?.c for a given architecture does not follow this pattern
and the file should be added to SRCS directly.

Reviewed by: emaste, imp, jhb
MFC after: 1 week
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D9841

r314558:
Garbage collect unused gdtoa related files on mips.

Reviewed by: emase, imp, jhb
MFC after: 1 week
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D9841

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Make armv6 hard float abi by default. Kill armv6hf.
Allow CPUTYPE=soft to build the current soft-float abi libraries.
Add UPDATING entry to announce this.

Approved by: re@ (gjb)

Clean up detection of hard-float ABIs. As with big-endian in r272368 we
can check against arm*hf*.

Remove MK_ARM_EABI, the armeb issues have been fixed. The code to support
the oabi is still in the tree, but it is expected this will be removed
as developers work on surrounding code.

With this commit the ARM EABI is the only supported supported ABI by
FreeBSD on ARMa 32-bit processors.

X-MFC after: never
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D876

Add the fp{get,set}{mask,round} functions to the public symbols in the map.
These are only exported for armv6hf as the soft-float ABIs have these in
the softfloat Symbol.map file.

Replace use of ${.CURDIR} by ${LIBC_SRCTOP} and define ${LIBC_SRCTOP}
if not already defined. This allows building libc from outside of
lib/libc using a reach-over makefile.

A typical use-case is to build a standard ILP32 version and a COMPAT32
version in a single iteration by building the COMPAT32 version using a
reach-over makefile.

Obtained from: Juniper Networks, Inc.

Add the required __aeabi_* functions to libc.

The floating point functions are here rather than compiler-rt because the
libc softfloat code allows us to set the rounding mode.

Use the compiler-rt version __{u,}divsi3 and __{u,}modsi3 on ARM EABI

Use GCC's __SOFTFP__ to test whether we're being compiled
with softfloat or not. Now -msoft-float can be overridden
more easily.

Add each directory's symbol map file to SYM_MAPS.

Use the correct values for softfloat, in both the little endian and the big
endian cases.

Eliminate gdtoa.mk and move its contents to ${MACHINE_ARCH}/Makefile.inc.
The purpose of having a separate file involved an abandoned scheme that
would have kept contrib/gdtoa out of the include path for the rest of libc.

Import a Makefile for arm.