[dmd-internals] bsr errors in 64

[David Simcha]

I'm trying to test out 64 support.  With the latest trunk everything, 
druntime compiles flawlessly.  Phobos compiles if I make core.stdc.math 
pure @safe.  Hello world compiles, but doesn't link.  The error message is:

undefined reference to `_D3std9intrinsic3bsrFNaNbmZi'

This error occurs in several places.