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

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

Fix the value of NT_FREEBSD_TAG to be the same as ABI_NOTRTYPE in lib/csu.
Add NT_FREEBSD_NOINIT_TAG for the value of CRT_NOINIT_NOTETYPE.
Check for both of these when detecting a FreeBSD binary in gdb.

Extend GDB to check the value in the .note.tag section along with the
.note.ABI-tag section.

This helps on ARM EABI where the OS/ABI field is zero. It would be better
to use the NOTES program header however this would require a more invasive
change.

This commit was generated by cvs2svn to compensate for changes in r130803,
which included commits to RCS files with non-trunk default branches.

Import of GDB version 6.1.1 (stripped; see FREEBSD-Xlist rev. 1.6).