llvm-symbolizer and llvm-addr2line allow to read addresses
from stdin, which makes them convenient to use in a context
where a large number of addresses should be resolved
(which may be too many to pass as command line arguments)
or not all addresses are known at the same time.
This patch adds a --addresses-from-stdin option to
llvm-gsymutil to allow the same.
clang-format not found in user’s local PATH; not linting file.