Issue warning if NEST is built without Boost

Author: heplesser

cmake/ConfigureSummary.cmake

@@ -261,6 +261,18 @@ function( NEST_PRINT_CONFIG_SUMMARY )
     message( "" )
   endif ()
 
+  if ( NOT HAVE_BOOST )
+    message( "" )
+    message( "ATTENTION!" )
+    message( "You are about to compile NEST without the Boost Library or" )
+    message( "your Boost Library is too old (before v1.70). This means" )
+    message( "that a few neuron models will not be available and that" )
+    message( "overall performance may be reduced." )
+    message( "" )
+    message( "--------------------------------------------------------------------------------" )
+    message( "" )
+  endif ()
+
   message( "You can now build and install NEST with" )
   message( "  make" )
   message( "  make install" )