diff --git a/configure/CONFIG_BASE b/configure/CONFIG_BASE
index 1957a8f56..70d68bb32 100644
--- a/configure/CONFIG_BASE
+++ b/configure/CONFIG_BASE
@@ -36,6 +36,7 @@ ifdef BASE_TOP
   SHRLIB_VERSION = $(EPICS_VERSION).$(EPICS_REVISION).$(EPICS_MODIFICATION)
   # Windows only allows 2 levels of version numbering
   PROD_VERSION = $(EPICS_VERSION).$(EPICS_REVISION)
+  BASE_CPPFLAGS += -DUSE_TYPED_RSET
 endif # BASE_TOP
 
 #---------------------------------------------------------------
@@ -45,7 +46,7 @@ endif # BASE_TOP
 OSITHREAD_USE_DEFAULT_STACK = NO
 OSITHREAD_DEFAULT_STACK_FLAGS_YES = -DOSITHREAD_USE_DEFAULT_STACK
 
-BASE_CPPFLAGS = $(OSITHREAD_DEFAULT_STACK_FLAGS_$(OSITHREAD_USE_DEFAULT_STACK))
+BASE_CPPFLAGS += $(OSITHREAD_DEFAULT_STACK_FLAGS_$(OSITHREAD_USE_DEFAULT_STACK))
 
 #---------------------------------------------------------------
 # Where to find the installed build tools