Use general hardening flag toggle lists

The following parameters are now available:

  * hardeningDisable
    To disable specific hardening flags
  * hardeningEnable
    To enable specific hardening flags

Only the cc-wrapper supports this right now, but these may be reused by
other wrappers, builders or setup hooks.

cc-wrapper supports the following flags:

  * fortify
  * stackprotector
  * pie (disabled by default)
  * pic
  * strictoverflow
  * format
  * relro
  * bindnow

pkgs/development/compilers/go/1.4.nix

@@ -20,7 +20,7 @@ stdenv.mkDerivation rec {
   buildInputs = [ pcre ];
   propagatedBuildInputs = lib.optional stdenv.isDarwin Security;
 
-  hardening_all = false;
+  hardeningDisable = [ "all" ];
 
   # I'm not sure what go wants from its 'src', but the go installation manual
   # describes an installation keeping the src.

pkgs/development/compilers/go/1.5.nix

@@ -29,7 +29,7 @@ stdenv.mkDerivation rec {
     Security Foundation
   ];
 
-  hardening_all = false;
+  hardeningDisable = [ "all" ];
 
   # I'm not sure what go wants from its 'src', but the go installation manual
   # describes an installation keeping the src.

pkgs/development/compilers/go/1.6.nix

@@ -29,7 +29,7 @@ stdenv.mkDerivation rec {
     Security Foundation
   ];
 
-  hardening_all = false;
+  hardeningDisable = [ "all" ];
 
   # I'm not sure what go wants from its 'src', but the go installation manual
   # describes an installation keeping the src.