File stack-check of Package x11vnc

diff --git a/src/Makefile.am b/src/Makefile.am
index 11168c7..12015cd 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -146,3 +146,8 @@ x11vnc_LDADD = \
 	@XI2_LIBS@ \
 	@CAIRO_LIBS@ \
 	$(LD_CYGIPC)
+
+CFLAGS_avahi.c = $(CFLAGS) -fstack-protector
+CFLAGS_connections.c = $(CFLAGS) -fstack-protector
+CFLAGS_uinput.c = $(CFLAGS) -fstack-protector
+CFLAGS_userinput.c = $(CFLAGS) -fstack-protector