Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Configure gcc to emit .note.GNU-stack for both 32 and 64 bits PowerPC.
Mark gcc-provided asm files as not requiring executable stack.

It seems that non-FreeBSD ABIs for powerpc64 claim stack non-executable.
Due to this, rs6000_elf_end_indicate_exec_stack() only emit the note for
32 bit target. I decided not to change FreeBSD ABI and patch
emit the notes for both variants.

Reviewed and tested by: nwhitehorn

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.

Gcc 3.4.2 20040728.

Enlist the FreeBSD-CURRENT users as testers of what is to become Gcc 3.1.0.
These bits are taken from the FSF anoncvs repo on 1-Feb-2002 08:20 PST.