fix problem with variable expansion

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@1906 5a81b35b-ba03-0410-adc8-b2c5c5119f08

CMakeLists.txt

@@ -121,7 +121,10 @@ else()
   set(LIB_STAGE_PATH "${STAGE_DIR}/lib")
 endif()
 
-file(MAKE_DIRECTORY $STAGE_DIR $EXECUTABLE_OUTPUT_PATH $HEADER_STAGE_PATH LIB_STAGE_PATH)
+file(MAKE_DIRECTORY ${STAGE_DIR} 
+     ${EXECUTABLE_OUTPUT_PATH} 
+     ${HEADER_STAGE_PATH}
+     ${LIB_STAGE_PATH})
 
 if (WIN32)
    # add_definitions(-DBOOST_TEST_INCLUDED)