SwiftWin32: enable tab control in ComCtl32

Enable the tab control behaviours for Common Controls to allow us to
build out some of the tab view handling.

Author: compnerd

Sources/SwiftWin32/App and Environment/ApplicationMain.swift

@@ -98,6 +98,7 @@ public func ApplicationMain(_ argc: Int32,
                    | DWORD(ICC_NATIVEFNTCTL_CLASS)
                    | DWORD(ICC_PROGRESS_CLASS)
                    | DWORD(ICC_STANDARD_CLASSES)
+                   | DWORD(ICC_TAB_CLASSES)
   var ICCE: INITCOMMONCONTROLSEX =
       INITCOMMONCONTROLSEX(dwSize: DWORD(MemoryLayout<INITCOMMONCONTROLSEX>.size),
                            dwICC: dwICC)

Sources/SwiftWin32/Support/WinSDK+Extensions.swift

@@ -147,6 +147,21 @@ internal var QS_ALLINPUT: DWORD {
   DWORD(QS_INPUT) | DWORD(QS_POSTMESSAGE) | DWORD(QS_TIMER) | DWORD(QS_PAINT) | DWORD(QS_HOTKEY) | DWORD(QS_SENDMESSAGE)
 }
 
+@_transparent
+internal var TCS_BOTTOM: DWORD {
+  DWORD(WinSDK.TCS_BOTTOM)
+}
+
+@_transparent
+internal var TCS_FIXEDWIDTH: DWORD {
+  DWORD(WinSDK.TCS_FIXEDWIDTH)
+}
+
+@_transparent
+internal var TCS_FLATBUTTONS: DWORD {
+  DWORD(WinSDK.TCS_FLATBUTTONS)
+}
+
 @_transparent
 internal var WS_BORDER: DWORD {
   DWORD(WinSDK.WS_BORDER)