diff --git a/CMake/PreventInSourceBuilds.cmake b/CMake/PreventInSourceBuilds.cmake
index 60f035f68683f500d71d7485c290bce4e0811b9a..2a402061c3e89b78c2055e2538e15d548d96a9c3 100644
--- a/CMake/PreventInSourceBuilds.cmake
+++ b/CMake/PreventInSourceBuilds.cmake
@@ -1,9 +1,14 @@
 #
 # This function will prevent in-source builds
 function(AssureOutOfSourceBuilds)
-  # make sure the user doesn't play dirty with symlinks
-  get_filename_component(srcdir "${CMAKE_SOURCE_DIR}" REALPATH)
-  get_filename_component(bindir "${CMAKE_BINARY_DIR}" REALPATH)
+  if (${CMAKE_MAJOR_VERSION}.${CMAKE_MINOR_VERSION} GREATER 2.6)
+    # make sure the user doesn't play dirty with symlinks
+    get_filename_component(srcdir "${CMAKE_SOURCE_DIR}" REALPATH)
+    get_filename_component(bindir "${CMAKE_BINARY_DIR}" REALPATH)
+  else()
+    get_filename_component(srcdir "${CMAKE_SOURCE_DIR}" ABSOLUTE)
+    get_filename_component(bindir "${CMAKE_BINARY_DIR}" ABSOLUTE)
+  endif()
 
   # disallow in-source builds
   if("${srcdir}" STREQUAL "${bindir}")