"make bootstrap" fails with

In file included from xlwmenu.c:41:0:
../src/xterm.h:78:23: error: missing binary operator before token "("
 #if GTK_CHECK_VERSION (2, 14, 0)
                        ^

I think this was introduced by

commit a1faaf3092cf47a274c1f9b93c312bf917a50b92
Author: Philipp Stephani <phst@google.com>
Date:   Fri Aug 25 11:08:25 2017 +0200

    Remove call of deprecated GDK function

    * src/xterm.h (XSync): Don’t call gdk_window_process_all_updates in
    GDK 3.22 or later.

At least, a1faaf3 fails to build, with the same error, but a1faaf3^ (the
prior changeset) builds okay.