macOS: Remove macOS 10.13 preprocessor checks

The current minimum-supported Xcode (10.1) includes the macOS 10.14.1
SDK, so APIs from macOS 10.13 will always be available.

modules/juce_core/native/juce_mac_SystemStats.mm

@@ -95,14 +95,12 @@ static String getOSXVersion()
         {
             const String systemVersionPlist ("/System/Library/CoreServices/SystemVersion.plist");
 
-           #if defined (MAC_OS_X_VERSION_10_13) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_13
             if (@available (macOS 10.13, *))
             {
                 NSError* error = nullptr;
                 return [NSDictionary dictionaryWithContentsOfURL: createNSURLFromFile (systemVersionPlist)
                                                            error: &error];
             }
-           #endif
 
             return [NSDictionary dictionaryWithContentsOfFile: juceStringToNS (systemVersionPlist)];
         }();

modules/juce_gui_basics/native/accessibility/juce_mac_Accessibility.mm

@@ -29,11 +29,6 @@ static void juceFreeAccessibilityPlatformSpecificData (NSAccessibilityElement<NS
 namespace juce
 {
 
-#if ! defined (MAC_OS_X_VERSION_10_13) || MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_13
- using NSAccessibilityRole = NSString*;
- using NSAccessibilityNotificationName = NSString*;
-#endif
-
 #define JUCE_NATIVE_ACCESSIBILITY_INCLUDED 1
 
 //==============================================================================
@@ -717,9 +712,7 @@ private:
                 return NO;
             });
 
-           #if defined (MAC_OS_X_VERSION_10_13) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_13
             addMethod (@selector (accessibilityChildrenInNavigationOrder), getAccessibilityChildren);
-           #endif
 
             registerClass();
         }

modules/juce_gui_basics/native/juce_mac_MainMenu.mm

@@ -293,11 +293,7 @@ public:
 
             [item setTag: topLevelIndex];
             [item setEnabled: i.isEnabled];
-           #if defined (MAC_OS_X_VERSION_10_13) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_13
             [item setState: i.isTicked ? NSControlStateValueOn : NSControlStateValueOff];
-           #else
-            [item setState: i.isTicked ? NSOnState : NSOffState];
-           #endif
             [item setTarget: (id) callback];
 
             auto* juceItem = new PopupMenu::Item (i);

modules/juce_gui_basics/native/juce_mac_NSViewComponentPeer.mm

@@ -1436,10 +1436,8 @@ public:
     {
         const auto type = []
         {
-           #if defined (MAC_OS_X_VERSION_10_13) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_13
             if (@available (macOS 10.13, *))
                 return NSPasteboardTypeFileURL;
-           #endif
 
             JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wdeprecated-declarations")
             return (NSString*) kUTTypeFileURL;

modules/juce_video/native/juce_mac_CameraDevice.h

@@ -341,10 +341,8 @@ private:
 
             const auto codecType = []
             {
-               #if defined (MAC_OS_X_VERSION_10_13) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_13
                 if (@available (macOS 10.13, *))
                    return AVVideoCodecTypeJPEG;
-               #endif
 
                 return AVVideoCodecJPEG;
             }();