Preprocessor: detect mobile platform (iOS vs Android)

platform.h

/**
 * NOTES:
 * - iOS: the useful macros are defined within TargetConditionals.h
 * - Android:
 *  - with Android.mk file(s) and the 'ndk-build' script (aka vanilla way),
 *    ANDROID is predefined (see -DANDROID extra C flag), 
 *  - with the Android Standalone Toolchain __ANDROID__ is predefined instead
 */
#if defined(__APPLE__)
  #include <TargetConditionals.h>
  #if TARGET_OS_IPHONE
    #define __SYSNAME_IOS__
    #define SYSNAME "ios"
  #endif
#elif defined(ANDROID) || defined(__ANDROID__)
  #define __SYS_ANDROID__
  #define SYSNAME "android"
#endif