MINOR: debug: add support for -dL to dump library names at boot

This is a second help to dump loaded library names late at boot, once
external code has already been initialized. The purpose is to provide
a format that makes it easy to pass to "tar" to produce an archive
containing the executable and the list of dependencies. For example
if haproxy is started as "haproxy -f foo.cfg", a config check only
will suffice to quit before starting, "-q" will be used to disable
undesired output messages, and -dL will be use to dump libraries.
This will result in such a command to trivially produce a tarball
of loaded libraries:

   ./haproxy -q -c -dL -f foo.cfg | tar -T - -hzcf archive.tgz

(cherry picked from commit 654726db5ab1160ad5dc8d356e2965e69c163dcf)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 6bba474149ec2432274efb8c96b69e748f9c90d4)
Signed-off-by: Willy Tarreau <w@1wt.eu>
3 files changed