diff --git a/cmake/Modules/PreventInSourceBuilds.cmake b/cmake/Modules/PreventInSourceBuilds.cmake
index 20d9d25590..31f2376aa1 100644
--- a/cmake/Modules/PreventInSourceBuilds.cmake
+++ b/cmake/Modules/PreventInSourceBuilds.cmake
@@ -5,10 +5,11 @@ function(prevent_in_source_builds)
   # make sure the user doesn't play dirty with symlinks
   get_filename_component(srcdir "${CMAKE_SOURCE_DIR}" REALPATH)
   get_filename_component(srcdir2 "${CMAKE_SOURCE_DIR}/.." REALPATH)
+  get_filename_component(srcdir3 "${CMAKE_SOURCE_DIR}/../src" REALPATH)
   get_filename_component(bindir "${CMAKE_BINARY_DIR}" REALPATH)
 
   # disallow in-source builds
-  if("${srcdir}" STREQUAL "${bindir}" OR "${srcdir2}" STREQUAL "${bindir}")
+  if("${srcdir}" STREQUAL "${bindir}" OR "${srcdir2}" STREQUAL "${bindir}" OR "${srcdir3}" STREQUAL "${bindir}")
     message(FATAL_ERROR "\
 
 CMake must not to be run in the source directory. \