Create Windows 7 spec files for core DLLs

To be able to create a realistic environment for Windows 7, we first need the appropriate exports for

• ntdll.dll
• kernel32.dll
• advapi32.dll
• gdi32.dll
• user32.dll
• comctl32.dll
• comdlg32.dll
• shell32.dll
• shlwapi.dll
• rpcrt4.dll
• msvcrt*.dll
  anything else?