--- a/make/autoconf/spec.gmk.in	Wed Apr 10 13:21:38 2019 +0200
+++ b/make/autoconf/spec.gmk.in	Wed Apr 10 07:04:35 2019 -0700
@@ -140,7 +140,9 @@
 
 # The top-level directory of the source repository
 TOPDIR:=@TOPDIR@
-
+# Usually the top level directory, but could be something else if a custom
+# root is defined.
+WORKSPACE_ROOT:=@WORKSPACE_ROOT@
 IMPORT_MODULES_CLASSES:=@IMPORT_MODULES_CLASSES@
 IMPORT_MODULES_CMDS:=@IMPORT_MODULES_CMDS@
 IMPORT_MODULES_LIBS:=@IMPORT_MODULES_LIBS@