Fix platform detection for iOS

[doubleday]

Platform detection fails for iOS resulting in compile error.

The TARGET_OS_MAC is a super category of TARGET_OS_OSX and TARGET_OS_IPHONE thus CATCH_PLATFORM_IPHONE is never selected.

From apple docs:

    TARGET_OS_* 
    These conditionals specify in which Operating System the generated code will
    run.  Indention is used to show which conditionals are evolutionary subclasses.  
    
    The MAC/WIN32/UNIX conditionals are mutually exclusive.
    The IOS/TV/WATCH conditionals are mutually exclusive.
    
    
        TARGET_OS_WIN32           - Generated code will run under 32-bit Windows
        TARGET_OS_UNIX            - Generated code will run under some Unix (not OSX) 
        TARGET_OS_MAC             - Generated code will run under Mac OS X variant
           TARGET_OS_OSX          - Generated code will run under OS X devices
           TARGET_OS_IPHONE          - Generated code for firmware, devices, or simulator
              TARGET_OS_IOS             - Generated code will run under iOS 
              TARGET_OS_TV              - Generated code will run under Apple TV OS
              TARGET_OS_WATCH           - Generated code will run under Apple Watch OS
              TARGET_OS_BRIDGE          - Generated code will run under Bridge devices
           TARGET_OS_SIMULATOR      - Generated code will run under a simulator
           TARGET_OS_EMBEDDED       - Generated code for firmware
       
        TARGET_IPHONE_SIMULATOR   - DEPRECATED: Same as TARGET_OS_SIMULATOR
        TARGET_OS_NANO            - DEPRECATED: Same as TARGET_OS_WATCH

      +------------------------------------------------+
      |                TARGET_OS_MAC                   |
      | +---+  +-------------------------------------+ |
      | |   |  |          TARGET_OS_IPHONE           | |
      | |OSX|  | +-----+ +----+ +-------+ +--------+ | |
      | |   |  | | IOS | | TV | | WATCH | | BRIDGE | | |
      | |   |  | +-----+ +----+ +-------+ +--------+ | |
      | +---+  +-------------------------------------+ |
      +------------------------------------------------+

[horenmar]

Can you add link to the docs?

[doubleday]

Well I just copied them from the header.

[doubleday]

But if you don't have access to a MAC this is one version for iOS:
https://github.com/mstg/iOS-full-sdk/blob/master/iPhoneOS9.3.sdk/usr/include/TargetConditionals.h

[horenmar]

I don't actually have a Mac.

Thanks