diff --git a/Makefile.unix b/Makefile.unix
index 806b9af1fb..811b0551e3 100644
--- a/Makefile.unix
+++ b/Makefile.unix
@@ -282,6 +282,8 @@ tools/cnvwindeps$(HOSTEXEEXT):
 # configured directories.
 
 Make.defs:
+	echo "include $(TOPDIR)$(DELIM).config" > Make.defs
+	echo "include $(TOPDIR)$(DELIM)tools$(DELIM)Config.mk" >> Make.defs
 
 # Link the arch/<arch-name>/include directory to include/arch
 
diff --git a/Makefile.win b/Makefile.win
index 9829c91341..32d42772c6 100644
--- a/Makefile.win
+++ b/Makefile.win
@@ -277,6 +277,8 @@ tools\mkdeps$(HOSTEXEEXT):
 # configured directories.
 
 Make.defs:
+	echo "include $(TOPDIR)$(DELIM).config" > Make.defs
+	echo "include $(TOPDIR)$(DELIM)tools$(DELIM)Config.mk" >> Make.defs
 
 # Link the arch\<arch-name>\include directory to include\arch