diff --git a/src/sbbs3/Common.gmake b/src/sbbs3/Common.gmake
index 38092dfcbf2fd210bc8449e51e2e466c5c453d35..35c4b0f450a652f12a23c83761b969f8ac29e942 100644
--- a/src/sbbs3/Common.gmake
+++ b/src/sbbs3/Common.gmake
@@ -40,4 +40,4 @@ vpath %.cpp $(SBBS_SRC)
 
 SBBSDEFS	:=
 -include sbbsdefs.mk		# defines $(SBBSDEFS)
-CFLAGS	+=	$(SBBSDEFS)
+MT_CFLAGS	+=	$(SBBSDEFS)
diff --git a/src/sbbs3/GNUmakefile b/src/sbbs3/GNUmakefile
index 7066169c535a6bb5458a5c1b97653bdbe111c488..d05854b703387f093238a1d6492b638e6848e4c1 100644
--- a/src/sbbs3/GNUmakefile
+++ b/src/sbbs3/GNUmakefile
@@ -79,7 +79,7 @@ CFLAGS	+=	$(JS_CFLAGS)
 LDFLAGS	+=	$(JS_LDFLAGS)
 
 include sbbsdefs.mk
-CFLAGS	+=	$(SBBSDEFS)
+MT_CFLAGS	+=	$(SBBSDEFS)
 
 # Set up LD_RUN_PATH for run-time locating of the .so files
 PWD	:=	$(shell pwd)
diff --git a/src/sbbs3/Makefile b/src/sbbs3/Makefile
index 9f8e2e729b4740cb02462019853bb6be5b092991..9050f8fa071a684ca2d928da56111f6e0be1dc5e 100644
--- a/src/sbbs3/Makefile
+++ b/src/sbbs3/Makefile
@@ -47,7 +47,7 @@ CFLAGS	=	$(CFLAGS) $(JS_CFLAGS)
 LDFLAGS	=	$(LDFLAGS) $(JS_LDFLAGS)
 
 !include sbbsdefs.mk
-CFLAGS	=	$(CFLAGS) $(SBBSDEFS)
+MT_CFLAGS	=	$(MT_CFLAGS) $(SBBSDEFS)
 
 CON_LIBS	= $(UL_PRE)sbbs$(UL_SUF) $(UL_PRE)ftpsrvr$(UL_SUF) $(UL_PRE)websrvr$(UL_SUF) $(UL_PRE)mailsrvr$(UL_SUF) $(UL_PRE)services$(UL_SUF)
 
diff --git a/src/sbbs3/sbbsdefs.mk b/src/sbbs3/sbbsdefs.mk
index f5ac094b6adb3d65c2a1aae120bf3c1c30438502..264902086bea3a2e58dea0bc5dc205e077b4c046 100644
--- a/src/sbbs3/sbbsdefs.mk
+++ b/src/sbbs3/sbbsdefs.mk
@@ -4,4 +4,4 @@
 
 # $Id$
 
-SBBSDEFS=	-DSBBS -DSBBS_EXPORTS -DSMB_EXPORTS -D_THREAD_SAFE -DRINGBUF_SEM
+SBBSDEFS=	-DSBBS -DSBBS_EXPORTS -DSMB_EXPORTS -DRINGBUF_SEM