diff --git a/src/converters/converter.h b/src/converters/converter.h
index 761ed4c..102dca5 100644
--- a/src/converters/converter.h
+++ b/src/converters/converter.h
@@ -52,7 +52,7 @@ namespace ts {
 
     CONVERTER_PRIMITIVE(int64_t);
     CONVERTER_PRIMITIVE(uint64_t);
-#if __x86_64__
+#if UINTPTR_WIDTH >= 64
     CONVERTER_PRIMITIVE(long_long_unsigned_int_t);
 #endif
     typedef std::string std__string;