* Make die_mem_offset() be able to handle DW_AT_data_member_location
attributes generated by Clang 3.4.
* Document how different compilers generate DW_AT_data_member_location
attributes differently.
* Document the quirks about DW_FORM_data[48].
This is a slightly modified version, adapted to work with the old
libdwarf in stable/9 and stable/10. It should fix DTrace on these
branches, when the kernel is compiled with clang 3.4.
Note that you have to build *and* install the CTF tools first, before
building the kernel. Otherwise you can possibly still get error
messages similar to "failed to copy type of 'pr_uid': Type information
is in parent and unavailable", when attempting to run dtrace(1).
Submitted by: kaiw
ebd9ec5dee