assign symbol indices before serializing symbols so forward-references

are possible

src/coff/coff_obj_writer.c

@@ -50,6 +50,7 @@ coff_obj_writer_serialize(Arena *arena, COFF_ObjWriter *obj_writer)
   // serialize symbol table
   //
   String8List symbol_table = {0};
+  {
     {
       U64 symbol_idx = 0;
       for (COFF_ObjSymbolNode *symbol_n = obj_writer->symbol_first; symbol_n != 0; symbol_n = symbol_n->next) {
@@ -57,6 +58,13 @@ coff_obj_writer_serialize(Arena *arena, COFF_ObjWriter *obj_writer)
 
         // assign symbol index
         s->idx = symbol_idx++;
+        symbol_idx += s->aux_symbols.node_count;
+      }
+    }
+
+    U64 symbol_idx = 0;
+    for (COFF_ObjSymbolNode *symbol_n = obj_writer->symbol_first; symbol_n != 0; symbol_n = symbol_n->next) {
+      COFF_ObjSymbol *s = &symbol_n->v;
 
       COFF_Symbol16 *d = push_array(scratch.arena, COFF_Symbol16, 1);
       str8_list_push(scratch.arena, &symbol_table, str8_struct(d));