On Hardened we add or remove some options like -fstack-check,
-fstack-protector-all, -fstrict_overflow and -z now

--- a/libgcc/Makefile.in	2011-11-22 04:01:02.000000000 +0100
+++ b/libgcc/Makefile.in	2011-12-25 15:18:22.449610631 +0100
@@ -225,7 +225,7 @@ endif
 LIBGCC2_DEBUG_CFLAGS = -g
 LIBGCC2_CFLAGS = -O2 $(LIBGCC2_INCLUDES) $(GCC_CFLAGS) $(HOST_LIBGCC2_CFLAGS) \
 		 $(LIBGCC2_DEBUG_CFLAGS) -DIN_LIBGCC2 \
-		 -fbuilding-libgcc -fno-stack-protector \
+		 -fbuilding-libgcc -fno-stack-protector -fstack-check=no \
 		 $(INHIBIT_LIBC_CFLAGS)
 
 # Additional options to use when compiling libgcc2.a.
@@ -279,7 +290,7 @@ INTERNAL_CFLAGS = $(CFLAGS) $(LIBGCC2_CF
   -finhibit-size-directive -fno-inline -fno-exceptions \
   -fno-zero-initialized-in-bss -fno-toplevel-reorder -fno-tree-vectorize \
   -fbuilding-libgcc -fno-stack-protector $(FORCE_EXPLICIT_EH_REGISTRY) \
-  $(INHIBIT_LIBC_CFLAGS)
+  -fstack-check=no $(INHIBIT_LIBC_CFLAGS)
 
 # Extra flags to use when compiling crt{begin,end}.o.
 CRTSTUFF_T_CFLAGS =
--- a/gcc/defaults.h	2016-01-04 15:30:50.000000000 +0100
+++ b/gcc/defaults.h	2016-05-02 22:23:43.815707806 +0200
@@ -1398,8 +1398,12 @@ see the files COPYING3 and COPYING.RUNTI
 /* Default value for flag_stack_protect when flag_stack_protect is initialized to -1:
    --enable-default-ssp: Default flag_stack_protect to -fstack-protector-strong.
    --disable-default-ssp: Default flag_stack_protect to 0.
+   Hardened: Default flag_stack_protect to -fstack-protector-all.
  */
 #ifdef ENABLE_DEFAULT_SSP
+# ifdef EXTRA_OPTIONS
+#  define DEFAULT_FLAG_SSP 2
+# endif
 # ifndef DEFAULT_FLAG_SSP
 #  define DEFAULT_FLAG_SSP 3
 # endif
--- a/gcc/gcc.c	2016-02-19 23:18:38.000000000 +0100
+++ b/gcc/gcc.c	2016-05-02 22:56:10.185721270 +0200
@@ -868,6 +868,13 @@ proper position among the other output f
 #endif
 #endif
 
+#define STACK_CHECK_SPEC "%{fstack-check|fstack-check=*:;: -fstack-check} "
+#ifdef EXTRA_OPTIONS
+#define LINK_NOW_SPEC "%{!nonow:-z now} "
+#else
+#define LINK_NOW_SPEC ""
+#endif
+
 #ifdef ENABLE_DEFAULT_PIE
 #define NO_PIE_SPEC		"no-pie|static"
 #define PIE_SPEC		NO_PIE_SPEC "|r|shared:;"
@@ -1013,7 +1020,7 @@ proper position among the other output f
     %(linker) " \
     LINK_PLUGIN_SPEC \
    "%{flto|flto=*:%<fcompare-debug*} \
-    %{flto} %{fno-lto} %{flto=*} %l " LINK_PIE_SPEC \
+    %{flto} %{fno-lto} %{flto=*} %l " LINK_PIE_SPEC LINK_NOW_SPEC \
    "%{fuse-ld=*:-fuse-ld=%*} " LINK_COMPRESS_DEBUG_SPEC \
    "%X %{o*} %{e*} %{N} %{n} %{r}\
     %{s} %{t} %{u*} %{z} %{Z} %{!nostdlib:%{!nostartfiles:%S}} \
@@ -1052,7 +1059,11 @@ proper position among the other output f
 
 static const char *asm_debug = ASM_DEBUG_SPEC;
 static const char *cpp_spec = CPP_SPEC;
+#ifdef EXTRA_OPTIONS
+static const char *cc1_spec = CC1_SPEC STACK_CHECK_SPEC;
+#else
 static const char *cc1_spec = CC1_SPEC;
+#endif
 static const char *cc1plus_spec = CC1PLUS_SPEC;
 static const char *link_gcc_c_sequence_spec = LINK_GCC_C_SEQUENCE_SPEC;
 static const char *link_ssp_spec = LINK_SSP_SPEC;
--- a/gcc/opts.c	2016-03-17 16:11:35.000000000 +0100
+++ b/gcc/opts.c	2016-04-27 16:48:59.952580580 +0200
@@ -495,7 +495,9 @@ static const struct default_options defa
     { OPT_LEVELS_2_PLUS, OPT_fschedule_insns2, NULL, 1 },
 #endif
     { OPT_LEVELS_2_PLUS, OPT_fstrict_aliasing, NULL, 1 },
+#ifndef EXTRA_OPTIONS
     { OPT_LEVELS_2_PLUS, OPT_fstrict_overflow, NULL, 1 },
+#endif
     { OPT_LEVELS_2_PLUS_SPEED_ONLY, OPT_freorder_blocks_algorithm_, NULL,
       REORDER_BLOCKS_ALGORITHM_STC },
     { OPT_LEVELS_2_PLUS, OPT_freorder_functions, NULL, 1 },