Restore link_all_deplibs on Debian/Ubuntu

Pro: this patch fixes #4, so can we work out of the box with Debian/Ubuntu libtool now.

Con: this patch makes bile rise up in the back of my throat.

I tried setting link_all_deplibs in a few places, but nothing propagated through to the generated libtool copy, so I'm resorting to a perl search-and-replace right after libtool is output.

It might be more portable to use sed here, but we're already using perl in update_license.pl anyway.