Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

MFC r262669:
When our linker merges .SUNW_dof sections from multiple files, it simply
concatenates the DOF tables into one section. Previously, the USDT init
code in drti.o would only look at the first table in the DOF section; with
this change, it iterates over all the tables, passing each DOF table to
the kernel.

PR: 186821

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

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

Cast away a clang alignment warning in drti.c's fixsymbol() function.
This code only runs on i386 and amd64, so there should be no problems if
buf + sec->dofs_offset is not aligned (which is unlikely anyway).

MFC after: 1 week

Disable debug by default.

Sponsored by: The FreeBSD Foundation

Add libdtrace support for tracing userland programs.

Summary of changes:
* Implement a compatibility shim between Solaris libproc and our
libproc and remove several ifdefs because of this.
* Port the drti to FreeBSD.
* Implement the missing DOODAD sections
* Link with libproc and librtld_db
* Support for ustack, jstack and uregs (by sson@)
* Misc bugfixing

When writing the SUWN_dof section, we had to resort to building the ELF
file layout by "hand". This is the job of libelf, but our libelf doesn't
support this yet. When libelf is fixed, we can remove the code under
#ifdef BROKEN_LIBELF.

Sponsored by: The FreeBSD Foundation

MFV OpenSolaris DTrace userland bits.

* Make this file compile cleanly.
* Add FreeBSD constructor/destructor definitions.

This commit was generated by cvs2svn to compensate for changes in r178528,
which included commits to RCS files with non-trunk default branches.

Vendor import of the full userland contrib part of DTrace support from
OpenSolaris. This commit resets files to match the versions in the
OpenSolaris tree as of 2008/04/10.

The changes in this import from the previous import are the ones that
will subsequently re-applied to take files off the vendor branch. This
is unfortunately necessary because the Solaris developers won't allow
FreeBSD support #ifdefs in their source code because that creates
'dead code' (stuff that they never compile).

Vendor import of libraries for DTrace from OpenSolaris.