diff --git a/configs/sim/nsh2/Make.defs b/configs/sim/nsh2/Make.defs
index b127e0a209e..39b33dc7dc9 100644
--- a/configs/sim/nsh2/Make.defs
+++ b/configs/sim/nsh2/Make.defs
@@ -49,6 +49,7 @@ ARCHPICFLAGS		= -fpic
 ARCHWARNINGS		= -Wall -Wstrict-prototypes -Wshadow
 ARCHWARNINGSXX		= -Wall -Wshadow
 ARCHDEFINES		=
+ARCHDEFINESXX		= -DCONFIG_WCHAR_BUILTIN
 ARCHINCLUDES		= -I. -isystem $(TOPDIR)/include
 ARCHINCLUDESXX		= -I. -isystem $(TOPDIR)/include -isystem $(TOPDIR)/include/cxx
 ARCHSCRIPT		=
@@ -66,7 +67,7 @@ OBJDUMP			= $(CROSSDEV)objdump
 CFLAGS			= $(ARCHWARNINGS) $(ARCHOPTIMIZATION) \
 			  $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
 CXXFLAGS		= $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) \
-			  $(ARCHCPUFLAGSXX) $(ARCHINCLUDESXX) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
+			  $(ARCHCPUFLAGSXX) $(ARCHINCLUDESXX) $(ARCHDEFINESXX) $(EXTRADEFINES) -pipe
 CPPFLAGS		= $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES)
 AFLAGS			= $(CFLAGS) -D__ASSEMBLY__