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/libraries/gdal/default.nix

@@ -18,7 +18,7 @@ composableDerivation.composableDerivation {} (fixed: rec {
   ++ (with pythonPackages; [ python numpy wrapPython ])
   ++ (stdenv.lib.optionals netcdfSupport [ netcdf hdf5 curl ]);
 
-  hardening_format = false;
+  hardeningDisable = [ "format" ];
 
   patches = [
     # This ensures that the python package is installed into gdal's prefix,

pkgs/development/libraries/gdal/gdal-1_11.nix

@@ -19,7 +19,7 @@ composableDerivation.composableDerivation {} (fixed: rec {
     ./python.patch
   ];
 
-  hardening_format = false;
+  hardeningDisable = [ "format" ];
 
   # Don't use optimization for gcc >= 4.3. That's said to be causing segfaults.
   # Unset CC and CXX as they confuse libtool.