Start working on c api

src/json_value.h

@@ -197,19 +197,19 @@ inline std::optional<JsonValue> toValue(std::string copy, int stride) {
   auto c = readValueCallbacks();
   parser3::Parser3 parser(&c, &state);
   if (stride == 0) {
-    if (parser.parse(copy.data(), copy.size()) != parser3::S_AGAIN) {
+    if (parser.parse(copy.data(), copy.size()) != WeaselJson_AGAIN) {
       return std::nullopt;
     }
   } else {
     for (int i = 0; i < copy.size(); i += stride) {
       if (parser.parse(copy.data() + i,
                        std::min<int>(stride, copy.size() - i)) !=
-          parser3::S_AGAIN) {
+          WeaselJson_AGAIN) {
         return std::nullopt;
       }
     }
   }
-  if (parser.parse(nullptr, 0) != parser3::S_OK) {
+  if (parser.parse(nullptr, 0) != WeaselJson_OK) {
     return std::nullopt;
   }
   return std::move(state.result);