SWPROT-8953: build: Allow packaging in project clients once

The client project should include cpack once,
the change prevents double inclusion

This help to use core as dependency for unify-z-wave

It was made for v7 but can also apply to v6, let's align before core pull.

Origin: #7
Signed-off-by: Philippe Coval <philippe.coval@silabs.com>

Author: rzr

cmake/include/package.cmake

@@ -1,13 +1,16 @@
 message(STATUS "Components of Unify which will have deb packages"
                ": ${CPACK_COMPONENTS_ALL}")
 
-include(CPack)
+if(PROJECT_IS_TOP_LEVEL)
+  message(STATUS "cpack: Included from ${CMAKE_SOURCE_DIR}")
+  include(CPack)
 
-foreach(PKG_NAME IN LISTS CPACK_COMPONENTS_ALL)
-      string(TOUPPER ${PKG_NAME} PKG_NAME_UPPER)
-  cpack_add_component(
-    PKG_NAME
-    DISPLAY_NAME ${PKG_NAME}
-    DESCRIPTION ${CPACK_DEBIAN_${PKG_NAME_UPPER}_DESCRIPTION}
-    INSTALL_TYPES Full)
-endforeach()
+  foreach(PKG_NAME IN LISTS CPACK_COMPONENTS_ALL)
+    string(TOUPPER ${PKG_NAME} PKG_NAME_UPPER)
+    cpack_add_component(
+      PKG_NAME
+      DISPLAY_NAME ${PKG_NAME}
+      DESCRIPTION ${CPACK_DEBIAN_${PKG_NAME_UPPER}_DESCRIPTION}
+      INSTALL_TYPES Full)
+  endforeach()
+endif()