This script seems to assume GNU grep, which is not commonly
available as "grep" on some platforms. For examples, it's
more common to have it named "ggrep" on BSD-based systems
including macOS.
Ideally, I suppose we should avoid GNU dependencies like this
in general. But I'm not motivated enough to rewrite this script
in a portable way today.
cf. https://www.gnu.org/software/grep/manual/grep.html#grep-Programs-1
The script can decode the backtrace dump, considering the syntax
of the backtrace format (properly handle the dump when SMP is
enabled, for instance) based on chip name or the toolchains's
addr2line tool.
