Help for the source built systems?

Does the Chromium build system use system libraries if they are new enough?
If the autoconf (or whatever build system chromium uses) could do a version
check on the system library at build time this might reduce the pain
somewhat.

One of the reasons I run a source based distro is so I can run with recent
libs on my system which is handy as a developer.

Of course this would involve keeping careful track of the divergence of
patches between the bundled libs and upstream. I'm guessing this is a wider
problem in free software that needs a decent solution.