diff --git a/CGAL_ipelets/demo/CGAL_ipelets/CMakeLists.txt b/CGAL_ipelets/demo/CGAL_ipelets/CMakeLists.txt
index b6419a7476c..80fcb5d2695 100644
--- a/CGAL_ipelets/demo/CGAL_ipelets/CMakeLists.txt
+++ b/CGAL_ipelets/demo/CGAL_ipelets/CMakeLists.txt
@@ -128,7 +128,9 @@ if ( CGAL_FOUND )
     set(CGAL_IPELETS ${CGAL_IPELETS} circle_pencils)
     set(CGAL_IPELETS ${CGAL_IPELETS} hyperbolic)
     set(CGAL_IPELETS ${CGAL_IPELETS} distance)
-    set(CGAL_IPELETS ${CGAL_IPELETS} cone_spanners)
+    if(CGAL_Core_FOUND)
+      set(CGAL_IPELETS ${CGAL_IPELETS} cone_spanners)
+    endif()
 
 
     if ( IPELET_INSTALL_DIR )
@@ -149,7 +151,9 @@ if ( CGAL_FOUND )
       endif ()
       cgal_add_compilation_test(CGAL_${IPELET})
     endforeach(IPELET)
-    target_link_libraries(CGAL_cone_spanners PRIVATE CGAL::CGAL_Core)
+    if(CGAL_Core_FOUND)
+      target_link_libraries(CGAL_cone_spanners PRIVATE CGAL::CGAL_Core)
+    endif()
     #example in doc not installed
     add_library(simple_triangulation MODULE simple_triangulation.cpp)
     add_to_cached_list(CGAL_EXECUTABLE_TARGETS simple_triangulation)
diff --git a/Installation/cmake/modules/CGAL_SetupLEDA.cmake b/Installation/cmake/modules/CGAL_SetupLEDA.cmake
index a221f67af6a..72688b361ec 100644
--- a/Installation/cmake/modules/CGAL_SetupLEDA.cmake
+++ b/Installation/cmake/modules/CGAL_SetupLEDA.cmake
@@ -42,7 +42,7 @@ function(use_CGAL_LEDA_support target)
     return()
   endif()
   separate_arguments(LIST_LEDA_CXX_FLAGS UNIX_COMMAND "${LEDA_CXX_FLAGS}")
-  separate_arguments(LIST_LEDA_DEFINITIONS UNIX_COMMAND "${LEDA_DEFINITIONS}")
+  separate_arguments(LIST_LEDA_DEFINITIONS UNIX_COMMAND "${LEDA_DEFINITIONS} -DCGAL_USE_LEDA")
 
   if(CMAKE_VERSION VERSION_LESS 3.3)
     target_compile_options(${target} ${keyword} ${LIST_LEDA_CXX_FLAGS})
diff --git a/Kernel_23/test/Kernel_23/CMakeLists.txt b/Kernel_23/test/Kernel_23/CMakeLists.txt
index 47e33a4d04f..4a2dec20634 100644
--- a/Kernel_23/test/Kernel_23/CMakeLists.txt
+++ b/Kernel_23/test/Kernel_23/CMakeLists.txt
@@ -8,7 +8,7 @@ cmake_minimum_required(VERSION 3.1)
 
 find_package(CGAL QUIET COMPONENTS Core)
 
-if ( CGAL_FOUND AND CGAL_Core_FOUND)
+if ( CGAL_FOUND )
 
   include(${CGAL_USE_FILE})
   include_directories (BEFORE "include")
diff --git a/Kernel_23/test/Kernel_23/include/CGAL/Precise_numbers.h b/Kernel_23/test/Kernel_23/include/CGAL/Precise_numbers.h
index 750164f104c..954c5bb4a74 100644
--- a/Kernel_23/test/Kernel_23/include/CGAL/Precise_numbers.h
+++ b/Kernel_23/test/Kernel_23/include/CGAL/Precise_numbers.h
@@ -23,6 +23,7 @@
 #ifndef CGAL_PRECISE_NUMBERS_H
 #define CGAL_PRECISE_NUMBERS_H
 
+#include <CGAL/config.h>
 #if defined CGAL_USE_GMPXX
 #  include <CGAL/gmpxx.h>
 typedef mpz_class                       Precise_integer;