After talking to mjw we decided that it was best to deliver this first in DTS and then later in RHEL.
elfutils 0.170 was released with partial DWARF5 support: libdw: Added new DWARF5 attribute, tag, character encoding, language code, calling convention, defaulted member function and macro constants to dwarf.h. New functions dwarf_default_lower_bound and dwarf_line_file. dwarf_peel_type now handles DWARF5 immutable, packed and shared tags. dwarf_getmacros now handles DWARF5 .debug_macro sections. This isn't full DWARF5 support, but it is all the DWARF5 you can encounter in "non-strict" DWARF mode (aka DWARF4 plus extensions that don't alter any data structures/forms). Which is enough for purposes of this bug/feature.
Made sure elfutils-0.168-8.el7 do not have the minimal DWARF5 support in terms of attached testcase 560859, and verified, that this minimal support is in place within devtoolset-7-elfutils-0.170-1.el{6,7}
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2017:3010