Detect and use SDL2 with help of this Dolphin CMake module:
https://github.com/dolphin-emu/dolphin/blob/master/CMakeTests/FindSDL2.cmake
Look for SDL_gamecontroller.h instead of SDL.h to prevent CMake from
using SDL1 include dirs
Update to SDL2
Update native submodule
Merge branch 'master' into sdl2

Conflicts:
	native
Replace frame download in danganronpa 2
Another replace frame download in danganronpa 2
Replace frame download in danganronpa 1
Another replace frame download in danganronpa 1
Add T2 and T3 to our register enum for clarity
Merge branch 'sdl2' of github.com:PGGB/ppsspp into PGGB-sdl2
Merge pull request #6978 from daniel229/replace_danganronpa

Replace frame download in danganronpa 1&2
Allow creation of window on custom screen set by SDL_VIDEO_FULLSCREEN_HEAD
Remove unnecessary files from Blackberry build package.
Revert "iOS: Add launch xib name to info.plist"

This reverts commit b7db78362db88852f99182b400e1a52603f2e259.
Revert "iOS: install LaunchScreen.xib"

This reverts commit 39716c68b3da13de88fe4b7c5ba068d70c84c9a8.
Revert "iOS: add LaunchScreen.xib for support iPhone 6 and 6 Plus native screen resolution"

This reverts commit 4dc6e268014d229fa7aa12cd3a5b163fbe15ff9f.
iOS: MacOS compatible post-build command
Merge pull request #6984 from AbandonedCart/master

Revert iPhone 6 changes (Temporarily), Fix iOS tar command
Fix Qt build in Linux, problem to recognize SDL2.