plasma-desktop: Prevent to check if a file exists in the host system

CMake triggers the build error:

| CMake Error at ConfigureChecks.cmake:5 (message):
|   Couldn't find XKB location: ./usr/share/X11/xkb.

Fix this ensuring xkb_base is not empty instead of checking if
a file exists.

recipes-kde/plasma/untier/plasma-desktop/files/0001-Ensure-xkb_base-is-not-empty-instead-of-checking-if-.patch

@@ -0,0 +1,27 @@
+From 424d64bdf12632bfd7d3331a4aef0f2bfdf7de8d Mon Sep 17 00:00:00 2001
+From: "Luis Gustavo S. Barreto" <gustavo@ossystems.com.br>
+Date: Thu, 12 Nov 2015 17:32:17 +0000
+Subject: [PATCH] Ensure xkb_base is not empty instead of checking if a file
+ exists
+
+Upstream-Status: Pending
+---
+ ConfigureChecks.cmake | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/ConfigureChecks.cmake b/ConfigureChecks.cmake
+index c7ea746..bd34032 100644
+--- a/ConfigureChecks.cmake
++++ b/ConfigureChecks.cmake
+@@ -1,7 +1,7 @@
+ set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules ${CMAKE_MODULE_PATH} )
+ 
+ execute_process(COMMAND ${PKG_CONFIG_EXECUTABLE} --variable=xkb_base xkeyboard-config OUTPUT_VARIABLE XKBDIR OUTPUT_STRIP_TRAILING_WHITESPACE)
+-if (NOT EXISTS "${XKBDIR}")
++if ("${XKBDIR}" STREQUAL "")
+     message(FATAL_ERROR "Couldn't find XKB location: .${XKBDIR}.")
+ endif()
+ set(KWIN_BIN "kwin_x11" CACHE STRING "Name of the KWin binary")
+-- 
+2.1.4
+

recipes-kde/plasma/untier/plasma-desktop/plasma-desktop.bb

@@ -45,6 +45,8 @@ PV = "${PLASMA_VERSION}"
 SRC_URI[md5sum] = "24dc314c2d6a8044d37f95bbb6faa7ba"
 SRC_URI[sha256sum] = "6649da817141096a6393648c834638ea0a09c1e799b1b300672c22c10c3bea8b"
 
+SRC_URI += "file://0001-Ensure-xkb_base-is-not-empty-instead-of-checking-if-.patch"
+
 FILES_SOLIBSDEV = "${libdir}/libkfont*${SOLIBSDEV}"
 
 FILES_${PN} += " \