Searching for a range match can cause the search order to not match
the sort order, which can cause libbacktrace to miss matching entries.
Allocate an extra entry at the end of function_addrs and unit_addrs vectors,
so that we can safely compare to the next entry when searching.
Adjust the matching code accordingly.
Fixes#44
* dwarf.c (function_addrs_search): Compare against the next entry
low address, not the high address.
(unit_addrs_search): Likewise.
(build_address_map): Add a trailing unit_addrs.
(read_function_entry): Add a trailing function_addrs.
(read_function_info): Likewise.
(report_inlined_functions): Search backward for function_addrs
match.
(dwarf_lookup_pc): Search backward for unit_addrs and
function_addrs matches.
This is a standalone version of the libbacktrace library that I
originally wrote for GCC. This is a copy of libbacktrace from GCC
trunk, with all dependencies incorporated here.
