buildsystem: fix debug broken by #3171 [backport]

config/functions

@@ -519,6 +519,10 @@ init_package_cache() {
       mv "${temp_global}" "${_CACHE_PACKAGE_GLOBAL}"
     fi
   fi
+
+  if [ -z "${_DEBUG_DEPENDS_LIST+x}" ]; then
+    set_debug_depends
+  fi
 }
 
 load_build_config() {

config/options

@@ -88,8 +88,6 @@ if [ "${OEM}" = "yes" -o "${OEM}" = "no" ]; then
   OEM_SUPPORT="${OEM}"
 fi
 
-[ -z "${_DEBUG_DEPENDS_LIST+x}" ] && set_debug_depends
-
 check_config
 
 . config/graphic