[OpenGL] Allow swap interval of -1 for adaptive sync, if supported

src/gl/inject.cpp

@@ -217,7 +217,7 @@ EXPORT_C_(bool) glXMakeCurrent(void* dpy, void* drawable, void* ctx) {
     if (ret)
         imgui_set_context(ctx);
 
-    if (params.gl_vsync >= 0) {
+    if (params.gl_vsync >= -1) {
         if (gl.glXSwapIntervalEXT)
             gl.glXSwapIntervalEXT(dpy, drawable, params.gl_vsync);
         if (gl.glXSwapIntervalSGI)

src/overlay_params.cpp

@@ -311,7 +311,7 @@ parse_overlay_config(struct overlay_params *params,
    params->reload_cfg = XK_F4;
    params->fps_limit = 0;
    params->vsync = -1;
-   params->gl_vsync = -1;
+   params->gl_vsync = -2;
    params->crosshair_size = 30;
    params->offset_x = 0;
    params->offset_y = 0;