trunk: bootstrap comparison failure

[Jan Hubicka]

> Now if this breaks other logic in ld & friends on have_cdtor targets, I guess we could

   0) return to always inlining on non_have_cdtors targets and hope for the best :)

>  1) du _sub_I/sub_D mangling only on targets not having ctors/dtors where merged constructor is always produced
>  2) make constructor merging to discover those specially named functions and
>     actually rename those specially called functions.
>  3) update collect2 to not collect static symbols
>  4) update the tools to also deal with sub_? variant.

Honza