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

ctf_add_type(): when looking up an integer or floating point type in the
list of pending dynamic type definitions, a match on the type name is not
sufficient - we need to compare the type encodings as well. For example,
bitfields have their own distinct type definitions which share the name of
the underlying integer type, and these types aren't generally
interchangeable.

This bug was causing the following libdtrace error when attempting to trace
the th_flags member of a struct tcphdr:
cg: bad field: off 104 type <32877> bits 539620016

Reported by: rwatson
MFC after: 3 weeks

When copying a type from a source CTF container to a destination container,
ctf_add_type() first performs a by-name lookup of the type in the
destination container. If this lookup returns a forward declaration for an
enum, struct, or union, reset dst_type back to CTF_ERR, indicating that the
source type is not in fact present in the destination container. This
ensures that ctf_add_type() will also search the destination container's
dynamic type list for the source type.

Without this change, a pair of mutually recursive struct definitions could
cause infinite recursion in ctf_add_type() if the destination container
only contained forward declarations for the struct types: ctf_add_type()
recursively calls itself on each struct member's type, and the forward
declarations meant that the dynamic type list search would be skipped.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

CTF containers use the ctf_dtoldid field as a threshold type index which
indicates the range of type indices which have been committed to the
container by ctf_update(). However, the top bit of the dtd_type field is
not part of the type index; rather, it is a flag used to indicate that the
corresponding CTF container is a parent. This is why the maximum CTF type
index is 2^15 - 1 rather than 2^16 - 1. Therefore, this flag must be masked
off (using the CTF_TYPE_TO_INDEX macro) when comparing a type index with the
ctf_dtoldid field of a container.

This bug was causing libctf to erroneously free committed type definitions
in ctf_discard(). libdtrace holds some references to such types, resulting
in a use-after-free.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

ctf_discard(): fetch the next list element before restarting the loop. If
we end up skipping a dynamic type because it has already been committed to
the container, we would previously either set the loop variable to an
uninitialized local variable, or set it to itself, resulting in an infinite
loop.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Quiesce warning assigning to void * from const ctf_header_t * by explicity casting
to void * before assignment.

Submitted as Illumos issue 4287

MFV r254422:

Illumos DTrace issues:
3089 want ::typedef
3094 libctf should support removing a dynamic type
3095 libctf does not validate arrays correctly
3096 libctf does not validate function types correctly

This commit was generated by cvs2svn to compensate for changes in r178525,
which included commits to RCS files with non-trunk default branches.

Vendor import of DTrace support files from OpenSolaris.