diff --git a/pjsip/build/Makefile b/pjsip/build/Makefile
index 849b2c3..a9c363b 100644
--- a/pjsip/build/Makefile
+++ b/pjsip/build/Makefile
@@ -51,7 +51,8 @@
 #
 export PJSIP_UA_SRCDIR = ../src/pjsip-ua
 export PJSIP_UA_OBJS += $(OS_OBJS) $(M_OBJS) $(CC_OBJS) $(HOST_OBJS) \
-			sip_inv.o sip_reg.o sip_replaces.o sip_xfer.o
+			sip_inv.o sip_reg.o sip_replaces.o sip_xfer.o \
+			sip_100rel.o
 export PJSIP_UA_CFLAGS += $(_CFLAGS)