-r no longer passed to linker under Linux?

I've just started seeing some projects fail to build under Linux with a recent clang, with this telltale message:

clang: warning: argument unused during compilation: '-r'

This is then followed by a load of missing symbol errors from the linker.

This definitely was working a few weeks ago, so it seems to be a regression...

David

This trivial patch fixes it, but I don't want to apply without understanding why it was broken in the first place...

David

Index: lib/Driver/Tools.cpp