Update source to SDL2 2.0.12

Edward Rudd

2020-05-02 03f8528315fa46c95991a34f3325d7b33ae5538c

 source/Xcode/SDL/Info-Framework.plist

@@ -19,10 +19,10 @@
   <key>CFBundlePackageType</key>
   <string>FMWK</string>
   <key>CFBundleShortVersionString</key>
   <string>2.0.9</string>
   <string>2.0.12</string>
   <key>CFBundleSignature</key>
   <string>SDLX</string>
   <key>CFBundleVersion</key>
   <string>2.0.9</string>
   <string>2.0.12</string>
</dict>
</plist>