Change the minimal SSP buffer size.

https://bugs.gentoo.org/484714
--- a/gcc/params.opt
+++ b/gcc/params.opt
@@ -1012,7 +1012,7 @@ Common Joined UInteger Var(param_ssa_name_def_chain_limit) Init(512) Param Optim
 The maximum number of SSA_NAME assignments to follow in determining a value.
 
 -param=ssp-buffer-size=
-Common Joined UInteger Var(param_ssp_buffer_size) Init(8) IntegerRange(1, 65536) Param Optimization
+Common Joined UInteger Var(param_ssp_buffer_size) Init(4) IntegerRange(1, 65536) Param Optimization
 The lower bound for a buffer to be considered for stack smashing protection.
 
 -param=stack-clash-protection-guard-size=