make: Clean up old lld libs from build directories since they break the build.

Makefile

@@ -128,6 +128,7 @@ toolchain: $(TOOLSTAMP)
 $(TOOLSTAMP):
 	-test -d _darcs && touch _darcs/patches/pending
 	rm -f $(OBJ)toolchain/{CMakeCache.txt,config.done}
+	rm -f $(OBJ){debug,semidbg,release}/clang/lib/liblld*
 	$(MAKE) config FLAVOUR=toolchain
 	$(CMAKE) --build $(OBJ)toolchain --target unwind_static -- $(EXTRA)
 	$(CMAKE) --build $(OBJ)toolchain --target cxxabi_static -- $(EXTRA)