The 'debugaltlink_name_len =+ 1' bug reported in PR89136 exposes the fact that
the build-id is not verified for the .gnu_debugaltlink.
Fix both problems.
2019-01-31 Tom de Vries <tdevries@suse.de>
PR libbacktrace/89136
* elf.c (elf_add): Read build-id if with_buildid_data. Fix
'debugaltlink_name_len =+ 1'.
From-SVN: r268419
