diff --git a/install/GNUmakefile b/install/GNUmakefile
index 3c6327baba9311c5f8e3dd0d94fa5c130403bacf..585c1554943290b0a9cd225f7c1053cc28fec7c0 100644
--- a/install/GNUmakefile
+++ b/install/GNUmakefile
@@ -141,7 +141,10 @@ ifndef NO_GTK
  endif
 endif
 
-all: binaries baja externals
+all: localdefs binaries baja externals
+
+localdefs: src
+	echo $(MKFLAGS) | tr ' ' '\n' > $(SBBSDIR)/src/build/localdefs.mk
 
 binaries:	sbbs3 gtkuseredit gtkchat gtkmonitor gtkuserlist syncview sexpots