MFC r312899: add octeon+ as an alias for octeon in GCC & binutils

r208737 added support for the "mips64r2" architecture and "octeon" CPU,
and the saa/saad instructions.

Upstream binutils also added the "octeon+" CPU, and the saa/saad
instructions are only available in octeon+, not octeon. Since our
base system tool chain already accepts saa/saad with -march=octeon,
just allow octeon+ as an alias.

This allows the use of octeon+ in kernel config files, for use with both
external tool chain and in-tree GCC/binutils.

Also includes GCC FBSD_CC_VER bump (r313041 in HEAD)

PR: 216516
Sponsored by: The FreeBSD Foundation

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

Add/improve mips64r2, Octeon, n32 and n64 support in the toolchain.

o) Add TARGET_ABI to the MIPS toolchain build process. This sets the default
ABI to one of o32, n32 or n64. If it is not set, o32 is assumed as that is
the current default.
o) Set the default GCC cpu type to any specified TARGET_CPUTYPE. This is
necessary to have a working "cc" if e.g. mips64 is specified, as binutils
will refuse to link objects using different ISAs in some cases.
o) Add support for n32 and n64 ABIs to binutils and GCC.
o) Add additional required libgcc2 stubs for n32 and n64.
o) Add support for the "mips64r2" architecture to GCC. Add the "octeon"
o) When static linking, wrap default libraries in --start-group and
--end-group. This is required for static linking to work on n64 with the
interdependencies between libraries there. This is what other OSes that
support n64 seem to do, as well.
o) Fix our GCC spec to define __mips64 for 64-bit targets, not __mips64__, the
former being what libgcc, etc., check and the latter seemingly being a
misspelling of a hand merge from a Linux spec.
o) When no TARGET_CPUTYPE is specified at build time, make GCC take the default
ISA from the ABI. Our old defaults were too liberal and assumed that 64-bit
ABIs should default to the MIPS64 ISA and that 32-bit ABIs should default to
the MIPS32 ISA, when we are supporting or will support some systems based on
earlier 32-bit and 64-bit ISAs, most notably MIPS-III.
o) Merge a new opcode file (and support code) from a later version of binutils
and add flags and code necessary to support Octeon-specific instructions.
This should also make merging opcodes for other modern architectures easier.

Reviewed by: imp

This commit was generated by cvs2svn to compensate for changes in r169689,
which included commits to RCS files with non-trunk default branches.

GCC 4.2.0 release.