Enforces that either static or dynamic libs are built

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 103cb1f..aae21a7 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -674,7 +674,9 @@ if(CGNS_BUILD_SHARED)
 endif()
 
 
+if(NOT CGNS_BUILD_SHARED)
 set (install_targets cgns_static)
+endif()
 if(CGNS_BUILD_SHARED)
   set(install_targets ${install_targets} cgns_shared)
 endif ()
@@ -738,7 +740,6 @@ install(EXPORT cgns-targets
 # Tools #
 #########
 
-add_subdirectory(tools)
 
 #########
 # Tests #