diff --git a/GNUmakefile b/GNUmakefile
index 65f829e..d4b04c6 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -384,7 +384,7 @@
 
   # 15d - multi-thread, debug, shared
   ifeq ($(BUILDTYPE),15d)
-    bmode = debug,pthreads,shared
+    bmode = debug,pthreads,shared,narrow
   endif   # ifeq ($(BUILDTYPE),15d)
 
   ifeq ($(BUILDTYPE),15D)