OS constants

The following constants are the possible values for the os_type variable.


 * os_win32: Windows 32bit executable.
 * os_win64: Windows 64bit executable.
 * os_macosx: Mac OSX.
 * os_psp: Playstation portable.
 * os_ios: Apple iOS (iPhone, iPad, iPod Touch etc.)
 * os_android: Android device (phone of tablet)