x11: Implement precision/pixel scrolling

Manual rebase of #5382 with some changes for SDL3 (thanks @wooosh).

Author: Kontrabant

cmake/sdlchecks.cmake

@@ -416,6 +416,17 @@ macro(CheckX11)
         endif()
         set(SDL_VIDEO_DRIVER_X11_XINPUT2 1)
 
+        # Check for scroll info
+        check_c_source_compiles("
+            #include <X11/Xlib.h>
+            #include <X11/Xproto.h>
+            #include <X11/extensions/XInput2.h>
+            XIScrollClassInfo *s;
+            int main(int argc, char **argv) {}" HAVE_XINPUT2_SCROLLINFO)
+        if(HAVE_XINPUT2_SCROLLINFO)
+          set(SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO 1)
+        endif()
+
         # Check for multitouch
         check_c_source_compiles_static("
             #include <X11/Xlib.h>

include/build_config/SDL_build_config.h.cmake

@@ -429,6 +429,7 @@
 #cmakedefine SDL_VIDEO_DRIVER_X11_XFIXES 1
 #cmakedefine SDL_VIDEO_DRIVER_X11_XINPUT2 1
 #cmakedefine SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH 1
+#cmakedefine SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_SCROLLINFO 1
 #cmakedefine SDL_VIDEO_DRIVER_X11_XRANDR 1
 #cmakedefine SDL_VIDEO_DRIVER_X11_XSCRNSAVER 1
 #cmakedefine SDL_VIDEO_DRIVER_X11_XSHAPE 1

src/video/x11/SDL_x11video.c

@@ -468,6 +468,7 @@ void X11_VideoQuit(SDL_VideoDevice *_this)
     }
 #endif
 
+    X11_QuitXinput2(_this);
     X11_QuitModes(_this);
     X11_QuitKeyboard(_this);
     X11_QuitMouse(_this);

src/video/x11/SDL_x11window.c

@@ -475,7 +475,7 @@ static void SetupWindowInput(SDL_VideoDevice *_this, SDL_Window *window)
     }
 #endif
 
-    X11_Xinput2SelectTouch(_this, window);
+    X11_Xinput2Select(_this, window);
 
     {
         unsigned int x11_keyboard_events = KeyPressMask | KeyReleaseMask;