add file

cmake/Modules/MacroEnsureOutOfSourceBuild.cmake

+# - MACRO_ENSURE_OUT_OF_SOURCE_BUILD(<errorMessage>)
+# MACRO_ENSURE_OUT_OF_SOURCE_BUILD(<errorMessage>)
+
+# Copyright (c) 2006, Alexander Neundorf, <neundorf@kde.org>
+#
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+
+macro (MACRO_ENSURE_OUT_OF_SOURCE_BUILD _errorMessage)
+
+   string(COMPARE EQUAL "${CMAKE_SOURCE_DIR}" "${CMAKE_BINARY_DIR}" _insource)
+   if (_insource)
+     message(SEND_ERROR "${_errorMessage}")
+     message(FATAL_ERROR "Remove the file CMakeCache.txt in ${CMAKE_SOURCE_DIR} first.")
+   endif (_insource)
+
+endmacro (MACRO_ENSURE_OUT_OF_SOURCE_BUILD)