* Add basic Insurgency support on Windows x64
This allows SourceMod to load on x64 Insurgency. There are still a lot of variable truncation warnings that have to be dealt with.
* Fix 32bit builds
* Compile MySQL extension as well
The hack for __iob_func being removed from the core runtime, but required by the old mysql we're building against can be simplified a lot due to the `_ReturnAddress` intrinsic available since MSVC 2015.
* Don't include the offset we want to extract in the signature
