jsoncpp: fix build with secure memory

jsoncpp changed the secure memory definition
with 1.9.7 and made it possible to enable it directly
via cmake.

Signed-off-by: Markus Theil <theil.markus@gmail.com>

pkgs/by-name/js/jsoncpp/package.nix

@@ -35,10 +35,6 @@ stdenv.mkDerivation (finalAttrs: {
     export sourceRoot=${finalAttrs.src.name}
   '';
 
-  postPatch = lib.optionalString secureMemory ''
-    sed -i 's/#define JSONCPP_USING_SECURE_MEMORY 0/#define JSONCPP_USING_SECURE_MEMORY 1/' include/json/version.h
-  '';
-
   nativeBuildInputs = [
     cmake
     python3
@@ -46,6 +42,7 @@ stdenv.mkDerivation (finalAttrs: {
   ];
 
   cmakeFlags = [
+    "-DJSONCPP_USE_SECURE_MEMORY=${if secureMemory then "ON" else "OFF"}"
     "-DBUILD_SHARED_LIBS=ON"
     "-DBUILD_OBJECT_LIBS=OFF"
     "-DJSONCPP_WITH_CMAKE_PACKAGE=ON"