macOS: Address more compiler warnings when building with a recent deployment target.

src/video/cocoa/SDL_cocoaevents.m

@@ -394,6 +394,7 @@ void
 Cocoa_PumpEvents(_THIS)
 { @autoreleasepool
 {
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 1070
     /* Update activity every 30 seconds to prevent screensaver */
     SDL_VideoData *data = (SDL_VideoData *)_this->driverdata;
     if (_this->suspend_screensaver && !data->screensaver_use_iopm) {
@@ -404,6 +405,7 @@ Cocoa_PumpEvents(_THIS)
             data->screensaver_activity = now;
         }
     }
+#endif
 
     for ( ; ; ) {
         NSEvent *event = [NSApp nextEventMatchingMask:NSEventMaskAny untilDate:[NSDate distantPast] inMode:NSDefaultRunLoopMode dequeue:YES ];

src/video/cocoa/SDL_cocoakeyboard.m

@@ -143,10 +143,13 @@
             aRange.location, aRange.length, windowHeight,
             NSStringFromRect(rect));
 
-    if ([window respondsToSelector:@selector(convertRectToScreen:)]) {
-        rect = [window convertRectToScreen:rect];
-    } else {
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 1070
+    if (![window respondsToSelector:@selector(convertRectToScreen:)]) {
         rect.origin = [window convertBaseToScreen:rect.origin];
+    } else
+#endif
+    {
+        rect = [window convertRectToScreen:rect];
     }
 
     return rect;

src/video/cocoa/SDL_cocoamessagebox.m

@@ -57,11 +57,24 @@
 - (void)showAlert:(NSAlert*)alert
 {
     if (nswindow) {
-        [alert beginSheetModalForWindow:nswindow modalDelegate:self didEndSelector:@selector(alertDidEnd:returnCode:contextInfo:) contextInfo:nil];
+#ifdef MAC_OS_X_VERSION_10_9
+        if ([alert respondsToSelector:@selector(beginSheetModalForWindow:completionHandler:)]) {
+            [alert beginSheetModalForWindow:nswindow completionHandler:^(NSModalResponse returnCode) {
+                clicked = returnCode;
+            }];
+        } else
+#endif
+        {
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 1090
+            [alert beginSheetModalForWindow:nswindow modalDelegate:self didEndSelector:@selector(alertDidEnd:returnCode:contextInfo:) contextInfo:nil];
+#endif
+        }
+
         while (clicked < 0) {
             SDL_PumpEvents();
             SDL_Delay(100);
         }
+
         [nswindow release];
     } else {
         clicked = [alert runModal];

src/video/cocoa/SDL_cocoavideo.h

@@ -86,7 +86,7 @@ static const unsigned int NSWindowStyleMaskUtilityWindow = NSUtilityWindowMask;
 static const unsigned int NSWindowStyleMaskDocModalWindow = NSDocModalWindowMask;
 #undef DECLARE_WINDOW_MASK
 
-#define DECLARE_ALERT_STYLE(name) static NSUInteger NSAlertStyle##name = NS##name##AlertStyle
+#define DECLARE_ALERT_STYLE(name) static const NSUInteger NSAlertStyle##name = NS##name##AlertStyle
 DECLARE_ALERT_STYLE(Warning);
 DECLARE_ALERT_STYLE(Informational);
 DECLARE_ALERT_STYLE(Critical);