Use Apple's nomenclature for macOS and iOS

Fixes https://github.com/libsdl-org/SDL/issues/6621

docs/README-android.md

@@ -369,7 +369,7 @@ Valgrind has support for Android out of the box, just grab code using:
 
 ... and follow the instructions in the file README.android to build it.
 
-One thing I needed to do on Mac OS X was change the path to the toolchain,
+One thing I needed to do on macOS was change the path to the toolchain,
 and add ranlib to the environment variables:
 export RANLIB=$NDKROOT/toolchains/arm-linux-androideabi-4.4.3/prebuilt/darwin-x86/bin/arm-linux-androideabi-ranlib
 

docs/README-ios.md

@@ -4,7 +4,7 @@ iOS
 Building the Simple DirectMedia Layer for iOS 9.0+
 ==============================================================================
 
-Requirements: Mac OS X 10.9 or later and the iOS 9.0 or newer SDK.
+Requirements: macOS 10.9 or later and the iOS 9.0 or newer SDK.
 
 Instructions:
 
@@ -233,7 +233,7 @@ Textures:
 	The optimal texture formats on iOS are SDL_PIXELFORMAT_ABGR8888, SDL_PIXELFORMAT_ABGR8888, SDL_PIXELFORMAT_BGR888, and SDL_PIXELFORMAT_RGB24 pixel formats.
 
 Loading Shared Objects:
-	This is disabled by default since it seems to break the terms of the iOS SDK agreement for iOS versions prior to iOS 8. It can be re-enabled in SDL_config_iphoneos.h.
+	This is disabled by default since it seems to break the terms of the iOS SDK agreement for iOS versions prior to iOS 8. It can be re-enabled in SDL_config_ios.h.
 
 
 Notes -- CoreBluetooth.framework
@@ -273,7 +273,7 @@ e.g.
     {
         ... initialize game ...
     
-    #if __IPHONEOS__
+    #ifdef __IOS__
         // Initialize the Game Center for scoring and matchmaking
         InitGameCenter();
     

docs/README-macos.md

@@ -1,7 +1,6 @@
-# Mac OS X (aka macOS).
+# macOS
 
-These instructions are for people using Apple's Mac OS X (pronounced
-"ten"), which in newer versions is just referred to as "macOS".
+These instructions are for people using Apple's macOS.
 
 From the developer's point of view, macOS is a sort of hybrid Mac and
 Unix system, and you have the option of using either traditional
@@ -21,8 +20,7 @@ sudo cmake --install .
 
 
 You can also build SDL as a Universal library (a single binary for both
-64-bit Intel and ARM architectures), by using the build-scripts/clang-fat.sh
-script.
+64-bit Intel and ARM architectures):
 
 ```bash
 mkdir build
@@ -32,10 +30,6 @@ cmake --build .
 sudo cmake --install .
 ```
 
-This script builds SDL with 10.9 ABI compatibility on 64-bit Intel and 11.0
-ABI compatibility on ARM64 architectures.  For best compatibility you
-should compile your application the same way.
-
 Please note that building SDL requires at least Xcode 6 and the 10.9 SDK.
 PowerPC support for macOS has been officially dropped as of SDL 2.0.2.
 32-bit Intel and macOS 10.8 runtime support has been officially dropped as
@@ -45,7 +39,7 @@ To use the library once it's built, you essential have two possibilities:
 use the traditional autoconf/automake/make method, or use Xcode.
 
 
-# Caveats for using SDL with Mac OS X
+# Caveats for using SDL with macOS
 
 If you register your own NSApplicationDelegate (using [NSApp setDelegate:]),
 SDL will not register its own. This means that SDL will not terminate using
@@ -133,17 +127,17 @@ there are some more things you should do before shipping your product...
 1. The bundle right now probably is dynamically linked against SDL. That
    means that when you copy it to another computer, *it will not run*,
    unless you also install SDL on that other computer. A good solution
-   for this dilemma is to static link against SDL. On OS X, you can
+   for this dilemma is to static link against SDL. On macOS, you can
    achieve that by linking against the libraries listed by
 
    ```bash
-   sdl-config --static-libs
+   sdl3-config --static-libs
    ```
 
    instead of those listed by
 
    ```bash
-   sdl-config --libs
+   sdl3-config --libs
    ```
 
    Depending on how exactly SDL is integrated into your build systems, the

docs/README-migration.md

@@ -5,6 +5,10 @@ This guide provides useful information for migrating applications from SDL 2.0 t
 We have provided a handy Python script to automate some of this work for you [link to script], and details on the changes are organized by SDL 2.0 header below.
 
 
+## SDL_platform.h
+
+The preprocessor symbol __MACOSX__ has been renamed __MACOS__, and __IPHONEOS__ has been renamed __IOS__
+
 ## SDL_pixels.h
 
 SDL_CalculateGammaRamp has been removed, because SDL_SetWindowGammaRamp has been removed as well due to poor support in modern operating systems (see [SDL_video.h](#sdl_videoh)).