Add SDL2.0.1-3742e768b536.

Note: using the same folder for future updates.

libs/SDL2/premake/README-macosx.txt

@@ -0,0 +1,34 @@
+Use the Xcode command files (located in the Xcode/build-scripts folder)
+to conveniently generate a workspace for Xcode 3 or Xcode 4. It also
+contains a cleaner script and a convenient script for automatically
+running all the test suites.
+
+If you use the script to automatically build the workspace file, you
+need to open the workspace at least once after generating it, or it
+will give errors that certain schema do not exist within the workspace.
+Also, the script depends on Xcode command line tools being installed.
+
+There are separate build files for building for i386 architecture
+versus x86_64 architecture. There are separate build scripts for
+Xcode 3 versus Xcode 4, but these just use the different toolchains.
+
+There is a script for automatically running through all known supported
+tests on that platform.
+
+The Mac OS X projects currently have reliance on the following dependencies:
+
+  -AudioToolbox.framework
+  -AudioUnit.framework
+  -Cocoa.framework
+  -CoreAudio.framework
+  -IOKit.framework
+  -Carbon.framework
+  -ForceFeedback.framework
+  -CoreFoundation.framework
+
+It will also link to OpenGL.framework, as the dependency function for OpenGL
+assumes that OpenGL always exists on Mac OS X. However, this is defined in
+a segmented way to allow the possibility of no OpenGL support on Mac OS X.
+
+Run the clean script to clear out the directory of Xcode-related files
+and binaries.