treewide: Do not limit hardenging because gcc 4.9 in bootstrap

Bootstrap tools has since been bumped

pkgs/tools/compression/xz/default.nix

@@ -17,9 +17,6 @@ stdenv.mkDerivation rec {
 
   postInstall = "rm -rf $out/share/doc";
 
-  # FIXME needs gcc 4.9 in bootstrap tools
-  hardeningDisable = [ "stackprotector" ];
-
   meta = with stdenv.lib; {
     homepage = http://tukaani.org/xz/;
     description = "XZ, general-purpose data compression software, successor of LZMA";

pkgs/tools/misc/coreutils/default.nix

@@ -21,9 +21,6 @@ stdenv.mkDerivation rec {
     sha256 = "0r8c1bgm68kl70j1lgd0rv12iykw6143k4m9a56xip9rc2hv25qi";
   };
 
-  # FIXME needs gcc 4.9 in bootstrap tools
-  hardeningDisable = [ "stackprotector" ];
-
   patches = optional hostPlatform.isCygwin ./coreutils-8.23-4.cygwin.patch;
 
   # The test tends to fail on btrfs and maybe other unusual filesystems.

pkgs/tools/system/which/default.nix

@@ -8,9 +8,6 @@ stdenv.mkDerivation rec {
     sha256 = "1bgafvy3ypbhhfznwjv1lxmd6mci3x1byilnnkc7gcr486wlb8pl";
   };
 
-  # FIXME needs gcc 4.9 in bootstrap tools
-  hardeningDisable = [ "stackprotector" ];
-
   meta = with stdenv.lib; {
     homepage = http://ftp.gnu.org/gnu/which/;
     platforms = platforms.all;