libtool & dependency_libs in *.la files

[Apologies if this has been covered before, but I cannot find anything in the archives] When building a package I noticed that binaries in the package were still getting unnecessary DT_NEEDED entries. Example: binary ---> depends only on libfoo.so | | libfoo depends on `----> libbar.so but the binary was getting built with DT_NEEDED entries for both 'libfoo.so' and 'libbar.so', which is wrong. ld had the '--no-add-needed' flag, so ld wasn't adding the extra DT_NEEDED entry. (See: http://fedoraproject.org/wiki/UnderstandingDSOLinkChange ) I tracked this down to our old friend libtool. Basically because the binary and the library were being built out of the same source tree, there was a 'libfoo.la' file which contained: dependency_libs='libbar.so' and this causes libtool to decide to "helpfully" add -lbar to the linker command line, even though it is completely unnecessary. (This is not a problem if libfoo and the binary were in separate source packages, because we already nuke the *.la files, which avoids this brokenness across different packages. The problem is specifically confined to the case where binaries and libraries are built from the *same* source package). I was able to work around this by adding a libtool wrapper which set dependency_libs='' in the *.la file. I notice that Debian, Ubuntu and Gentoo have proposed something similar: http://wiki.debian.org/ReleaseGoals/LAFileRemoval http://lists.debian.org/debian-devel/2009/08/msg00783.html http://lists.debian.org/debian-release/2009/08/msg00217.html http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=586082 except they are unilaterally modifying libtool downstream instead of using my hackish wrapper, which is a better idea. Apparently either no one has tried to get this upstream, or libtool developers weren't listening. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://et.redhat.com/~rjones/virt-top