I wrote a patch to give glibc support for profiling multiple shared libraries at once. Right now if you set the environment variable LD_PROFILE to the name of a shared library, glibc will generate gprof style profiling information for that library without you recompiling anything. But that only works with one library at a time. I sent a patch to fix this limitation to the glibc maintainer before the New Year and I've heard nothing back from him yet. Bummer... I don't know if there was something wrong with it, or if it's just not something he's interested in.
I guess I can put the patch up on a web page and let people find it through google. But it seems almost pointless, as it's only a matter of time before the offical codebase moves on and the patch gets stale.