Wayland: Fix protocol error on undecorated window

When setting the visibility of a libdecor frame on a compositor that
supports XDG decorations, libdecor 0.1 will update the geometry of the
XDG surface.  GLFW attempted to set the visibility before having told
libdecor what size the content area is.  This caused a Wayland protocol
error when libdecor attempted to set the window size to 0x0.

This commit adds setting the content area size for the libdecor frame
directly after creation, allowing libdecor to know what it's doing.

README.md

@@ -387,6 +387,7 @@ information on what to include when reporting a bug.
  - [Wayland] Bugfix: Connecting a mouse after `glfwInit` would segfault (#1450)
  - [Wayland] Bugfix: Joysticks connected after `glfwInit` were not detected (#2198)
  - [Wayland] Bugfix: Fallback decorations emitted `GLFW_CURSOR_UNAVAILABLE` errors
+ - [Wayland] Bugfix: Showing an undecorated window would cause a protocol error
  - [POSIX] Removed use of deprecated function `gettimeofday`
  - [POSIX] Bugfix: `CLOCK_MONOTONIC` was not correctly tested for or enabled
  - [Linux] Bugfix: Joysticks without buttons were ignored (#2042,#2043)

src/wl_window.c

@@ -750,6 +750,11 @@ static GLFWbool createLibdecorFrame(_GLFWwindow* window)
         return GLFW_FALSE;
     }
 
+    struct libdecor_state* frameState =
+        libdecor_state_new(window->wl.width, window->wl.height);
+    libdecor_frame_commit(window->wl.libdecor.frame, frameState, NULL);
+    libdecor_state_free(frameState);
+
     if (strlen(window->wl.appId))
         libdecor_frame_set_app_id(window->wl.libdecor.frame, window->wl.appId);