fix old cmake behavior

HySoP/src/CMakeLists.txt

@@ -85,7 +85,11 @@ if(WITH_FFTW)
   #set(FFTWLIB ${FFTW_LIBRARIES} CACHE PATH "fftw libraries dir")
   set(dirlist)
   foreach(_file ${FFTW_LIBRARIES})
-    get_filename_component(_name ${_file} DIRECTORY)
+    if(CMAKE_PATCH_VERSION LESS 12)
+      get_filename_component(_name ${_file} REALPATH)
+    else()
+      get_filename_component(_name ${_file} DIRECTORY)
+    endif()
     list(FIND dirlist ${_name} isin)
     if(isin EQUAL -1)
       list(APPEND dirlist ${_name})
@@ -94,6 +98,8 @@ if(WITH_FFTW)
   set(FFTWLIB ${dirlist} CACHE PATH "fftw libraries dir")
 endif()
 display(FFTWLIB)
+
+
 # ============= Generates ParmesConfig.hpp =============
 # The file PARMES_LIBRARY_NAME_defines.hpp will be generated from config.hpp.cmake;
 if(EXISTS ${CMAKE_SOURCE_DIR}/config.hpp.cmake)