build: enable increased reliability of stack overflow detection

See https://developers.redhat.com/blog/2018/03/21/compiler-and-linker-flags-gcc/

diff --git a/configure.ac b/configure.ac
index 589cd969fd5eb55bdedd666ad525311ad3a2a9fa..ef4ad69c4ed271ee997d66411c4bb6aa6c99aa64 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -108,6 +108,7 @@ if test x"$hardening" != x"no"; then
   AX_CFLAGS_GCC_OPTION([-fstack-protector-all], [LLDP_CFLAGS])
   AX_CFLAGS_GCC_OPTION([-fstack-protector-strong], [LLDP_CFLAGS])
   AX_CFLAGS_GCC_OPTION([-fstack-protector-strong], [LLDP_CFLAGS])
+  AX_CFLAGS_GCC_OPTION([-fstack-clash-protection], [LLDP_CFLAGS])
   AX_CFLAGS_GCC_OPTION([-D_FORTIFY_SOURCE=2], [LLDP_CPPFLAGS])
 fi
 if test x"$pie" = x"yes"; then