Commit improved version of 111026 & 111027.

Unused warnings for functions:
-static functions
-functions in anonymous namespace
-class methods in anonymous namespace
-class method specializations in anonymous namespace
-function specializations in anonymous namespace

Unused warnings for variables:
-static variables
-variables in anonymous namespace
-static data members in anonymous namespace
-static data members specializations in anonymous namespace

Reveals lots of opportunities for dead code removal in llvm codebase that will
interest my esteemed colleagues.

llvm-svn: 111086