desired, one can turn off the generation of post-ELF standard dtags by
overriding it with --disable-new-dtags after the default switch.
Immediate effect of the change is that -rpath path is now stored both
in DT_RPATH and DT_RUNPATH tags, which is the right way to provide
rpath for dynamic linker supporting DT_RUNPATH per specification.
Reviewed by: kan
MFC after: 1 month