(dg-gpp-additional-sources): New function.
(dg-gpp-additional-files): Likewise.
* lib/g++.exp (additional_sources): New variable.
(additional_files): Likewise.
(g++_target_compile): Deal with them.
* lib/old-dejagnu.exp: Remove.
* g++.old-deja/old-deja.exp: Use dg.exp, not old-dejagnu.exp.
* g++.old-deja: Revise all tests to use dg commands.