libobs-opengl: Check window creation for errors

Without this we get somewhat misleading errors from later in the
swapchain creation when this fails. This is currently happening for
users attempting to use multi-gpu with prime offloading on nvidia.

libobs-opengl/gl-x11-egl.c

@@ -416,9 +416,20 @@ static bool gl_x11_egl_platform_init_swapchain(struct gs_swap_chain *swap)
 	xcb_create_colormap(xcb_conn, XCB_COLORMAP_ALLOC_NONE, colormap, parent,
 			    visual);
 
-	xcb_create_window(xcb_conn, 24 /* Hardcoded? */, wid, parent, 0, 0,
-			  geometry->width, geometry->height, 0, 0, visual, mask,
-			  mask_values);
+	xcb_void_cookie_t window_cookie = xcb_create_window_checked(
+		xcb_conn, 24 /* Hardcoded? */, wid, parent, 0, 0,
+		geometry->width, geometry->height, 0, 0, visual, mask,
+		mask_values);
+	xcb_generic_error_t *err = xcb_request_check(xcb_conn, window_cookie);
+	if (err != NULL) {
+		char text[512];
+		XGetErrorText(display, err->error_code, text, sizeof(text));
+		blog(LOG_ERROR,
+		     "Swapchain window creation failed: %s"
+		     ", Major opcode: %d, Minor opcode: %d",
+		     text, err->major_code, err->minor_code);
+		goto fail_window_surface;
+	}
 
 	const EGLSurface surface =
 		eglCreateWindowSurface(plat->edisplay, plat->config, wid, 0);