Unbreak the build on win32.

Unbreak the build on win32.
Cleanup some warning.

Remark: when struct/class are declared differently than they are defined, this make problem for VC++ since it seems to mangle class differently that struct. These error are very hard to understand and find. So please, try to keep your definition/declaration in sync.

Only tested with VS2008. hope it does not break anything. feel free to revert.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64554 91177308-0d34-0410-b5e6-96231b3b80d8