Fix warning in GL ES2 renderer

Separate EGL / GL ES detection in CMake

XAudio2/DirectSound: Use the usual Windows string convert (thanks, Norfanin!).

Added SDL_VIDEO_OPENGL_ES2 to the SDL_config.h templates (Thanks, Kerim!).

Fixes #2036 and #2038, bypass camera zoom and shutter keypresses on Android.

Fixed compiling on old versions of the DirectX SDK

SDL
- detect that you tried to open a gamecontroller in xinput mode and failed, then re-get the mapping for the dinput variant you did open (and most likely now just fail the open)

CR: SamL

Fix SDL xinput code to work at all when xinput has devices at high indexes but no device connected at lower index, for instance 0->disconnected, 1->wireles, 2->wired. Previously the SDL code assumed the indexes were always used up in order which is not true at all and lead to a bunch of failure cases where controllers would go unrecognized.

This entire function is kind of a mess and more complicated than needed, but I don't want to refactor it too heavily tonight. May look at improving how the indexes are assigned more significanly later. The way it handles not finding a valid "gamepad" type device is also super broken, it leaves in place the xinput bindings but opens the controller with dinput and ends up with completely wrong mappings, not solving that now, but fixing the bug where we'd very frequently not find a controller due to gaps in assigned player numbers should mostly avoid it.

Fixed crash if the IC isn't set up for some reason (bad X11 locale?)

Fix a couple of warnings