MSVC hook function prologue

[Stefan Dösinger]

> Are there non-Microsoft DLLs that expect to be hooked this way?  If
> so, I think the patch is interesting for gcc independent of whether it
> is useful for Wine.
I haven't seen any so far. Its certainly possible some server apps  
have the 2 byte nop at the beginning of functions for a similar hot- 
patching mechanism, but beyond that I don't think any app needs this.