Why are we linking with --as-needed?

[Guy Harris <guy () alum mit edu>]

The GNU linker documentation says of the --as-needed flag

--as-needed
--no-as-needed
        This option affects ELF DT_NEEDED tags for dynamic libraries mentioned on the command line after the 
--as-needed option. Normally the linker will add a DT_NEEDED tag for each dynamic library mentioned on the command 
line, regardless of whether the library is actually needed or not.  --as-needed causes a DT_NEEDED tag to only be 
emitted for a library that at that point in the link satisfies a non-weak undefined symbol reference from a regular 
object file or, if the library is not found in the DT_NEEDED lists of other needed libraries, a non-weak undefined 
symbol reference from another needed dynamic library. Object files or libraries appearing on the command line after the 
library in question do not affect whether the library is seen as needed. This is similar to the rules for extraction of 
object files from archives.  --no-as-needed restores the default behaviour.

--as-needed was added in this change:

        commit b6cffe405019da8259413cfcb829339712a098a7
        Author: Jörg Mayer <jmayer () loplof de>
        Date:   Fri Aug 7 18:49:24 2009 +0000

            - Add an AC macro to test linker flags.
            - Test whether the linker supports --as-needed and if so,
              adds it to LDFLAGS

About all I could find for a reason were bugs such as

        https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=1677

complaining that Wireshark didn't build with --as-needed.

So why is it useful that it be built - or, at least, buildable - with --as-needed?  (It's obviously not *necessary* as 
not all platform support that capability.)
___________________________________________________________________________
Sent via:    Wireshark-dev mailing list <wireshark-dev () wireshark org>
Archives:    https://www.wireshark.org/lists/wireshark-dev
Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev
             mailto:wireshark-dev-request () wireshark org?subject=unsubscribe