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 section .note.GNU-stack for assembly files used by 386 and amd64.

We've been lax about matching END() macros in asm code for some time. This
is used to set the ELF size attribute for functions. It isn't normally
critical but some things can make use of it (gdb for stack traces).
Valgrind needs it so I'm adding it in. The problem is present on all
branches and on both i386 and amd64.

Rewrite fabs.S to use pure SSE2 operations. I got the clues how to do
this from looking at code generated by gcc.

Fix fabs(). This commit brought to you by the letter 'l'.
(fstp stores a mem32 value, fstpl stores a mem64 value)

This fixes ghostscript for 'make release' on amd64. Ghostscript for some
reason thinks it is a good idea to use -fno-builtin, which means it is
vulnerable to bugs in libc that are normally hidden by the builtin gcc
functions. Oops.

Floating point libc functions traditionally written in ASM.
AMD64 does away with the x87 in 64-bit long mode, so we have to play the
SSE/SSE2 game now.

Obtained from: NetBSD/x86-64