fix symbols for ABI

Author: umanwizard

js/addon2.cpp

@@ -13,6 +13,10 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+extern "C" {
+  __thread custom_labels_hashmap_t *custom_labels_async_hashmap;
+}
+
 namespace custom_labels {
 using v8::FunctionCallbackInfo;
 using v8::Isolate;
@@ -22,7 +26,6 @@ using v8::Object;
 using v8::String;
 using v8::Value;
 
-__thread custom_labels_hashmap_t *custom_labels_async_hashmap;
 
 #define hm custom_labels_async_hashmap
 

src/customlabels.cpp

@@ -10,8 +10,10 @@
 
 #define MAX(a,b) ((a) > (b) ? (a) : (b))
 
-__attribute__((retain))
-const uint32_t custom_labels_abi_version = 1;
+extern "C" {
+  __attribute__((retain))
+    uint32_t custom_labels_abi_version = 1;
+}
 
 struct _custom_labels_ls {
   custom_labels_label_t *storage;