disable xwayland module if exe cannot be found during configure

should probably make this a --flag at some point

fix T3415

configure.ac

@@ -772,6 +772,9 @@ define([CHECK_MODULE_XWAYLAND],
   if test "x${have_wayland}" = "xyes"; then
     AC_E_CHECK_PKG(XWAYLAND, [ ecore-x >= ${efl_version} ecore-audio >= ${efl_version}  ], [HAVE_XWAYLAND_DEPS=true], [HAVE_XWAYLAND_DEPS=false])
     AC_PATH_PROG([XWAYLAND_BIN], [Xwayland], [false])
+    if test "x${XWAYLAND_BIN}" = "xfalse"; then
+      HAVE_XWAYLAND_DEPS=false
+    fi
   else
     HAVE_XWAYLAND_DEPS=false
   fi