core: Add Insurgency support for amd64 Windows (#1295)

* 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

AMBuildScript

@@ -97,6 +97,8 @@ def SetArchFlags(compiler, arch, platform):
       compiler.linkflags += ['/MACHINE:X86']
     elif builder.target.arch == 'x64':
       compiler.linkflags += ['/MACHINE:X64']
+    if arch == 'x64':
+      compiler.defines += ['WIN64']
 
 def AppendArchSuffix(binary, name, arch):
   if arch == 'x64':
@@ -180,19 +182,19 @@ class SMConfig(object):
     self.mms_root = Normalize(self.mms_root)
 
     if builder.options.hasMySql:
-      if builder.options.mysql_path:
-        self.mysql_root['x86'] = builder.options.mysql_path
-      else:
-        for i in range(10):
-          self.mysql_root['x86'] = ResolveEnvPath('MYSQL55', 'mysql-5.' + str(i))
-          if self.mysql_root['x86']:
-            break
-      if not self.mysql_root['x86'] or not os.path.isdir(self.mysql_root['x86']):
-        raise Exception('Could not find a path to MySQL!')
-      self.mysql_root['x86'] = Normalize(self.mysql_root['x86'])
+      if 'x86' in self.archs:
+        if builder.options.mysql_path:
+          self.mysql_root['x86'] = builder.options.mysql_path
+        else:
+          for i in range(10):
+            self.mysql_root['x86'] = ResolveEnvPath('MYSQL55', 'mysql-5.' + str(i))
+            if self.mysql_root['x86']:
+              break
+        if not self.mysql_root['x86'] or not os.path.isdir(self.mysql_root['x86']):
+          raise Exception('Could not find a path to MySQL!')
+        self.mysql_root['x86'] = Normalize(self.mysql_root['x86'])
 
-      # For now, ignore 64-bit MySQL on Windows
-      if 'x64' in self.archs and builder.target.platform != 'windows':
+      if 'x64' in self.archs:
         if builder.options.mysql64_path:
           self.mysql_root['x64'] = builder.options.mysql64_path
         else:
@@ -490,6 +492,7 @@ class SMConfig(object):
 
   def ExtLibrary(self, context, name, arch):
     binary = self.Library(context, name, arch)
+    SetArchFlags(binary.compiler, arch, builder.target.platform)
     self.ConfigureForExtension(context, binary.compiler)
     return binary
 
@@ -533,7 +536,11 @@ class SMConfig(object):
       compiler.defines.remove('_vsnprintf=vsnprintf')
 
     if compiler.like('msvc'):
-      compiler.defines += ['COMPILER_MSVC', 'COMPILER_MSVC32']
+      compiler.defines += ['COMPILER_MSVC']
+      if arch == 'x86':
+        compiler.defines += ['COMPILER_MSVC32']
+      elif arch == 'x64':
+        compiler.defines += ['COMPILER_MSVC64']
       compiler.linkflags += ['legacy_stdio_definitions.lib']
     else:
       compiler.defines += ['COMPILER_GCC']
@@ -611,7 +618,10 @@ class SMConfig(object):
       if sdk.name in ['swarm', 'blade', 'insurgency', 'doi', 'csgo']:
         libs.append('interfaces')
       for lib in libs:
-        lib_path = os.path.join(sdk.path, 'lib', 'public', lib) + '.lib'
+        if arch == 'x86':
+          lib_path = os.path.join(sdk.path, 'lib', 'public', lib) + '.lib'
+        elif arch == 'x64':
+          lib_path = os.path.join(sdk.path, 'lib', 'public', 'win64', lib) + '.lib'
         compiler.linkflags.append(compiler.Dep(lib_path))
 
     for library in dynamic_libs: