cmake: setup variable WORDS_BIGENDIAN correctly

Since version 3.0 cmake provides the macro test_big_endian for
that purpose.

fixes #375

Signed-off-by: Ralf Habacker <ralf.habacker@freenet.de>
(cherry picked from commit d74fee2727)
Backported-from: dbus!266

CMakeLists.txt

@@ -28,6 +28,10 @@ include(MacrosAutotools)
 autoinit(configure.ac)
 autoversion(dbus)
 
+# replacement for AC_C_BIGENDIAN
+include (TestBigEndian)
+test_big_endian(WORDS_BIGENDIAN)
+
 if(EXISTS ${CMAKE_SOURCE_DIR}/config.h.in)
     autoheaderchecks(${CMAKE_SOURCE_DIR}/config.h.in ${CMAKE_SOURCE_DIR}/cmake/ConfigureChecks.cmake ${CMAKE_SOURCE_DIR}/cmake/config.h.cmake)
 else()

cmake/config.h.cmake

@@ -21,6 +21,9 @@
  * should be placed in this file
 */
 
+/* AC_C_BIGENDIAN */
+#cmakedefine WORDS_BIGENDIAN
+
 /* Opt-in to modern APIs and thread-safety for Solaris. In the Autotools
  * build system we do the equivalent of this by appending to CFLAGS
  * in configure.ac */