diff --git a/core/my_basic.c b/core/my_basic.c
index 788cf43..669d9f0 100755
--- a/core/my_basic.c
+++ b/core/my_basic.c
@@ -404,7 +404,9 @@ typedef void (* _unref_func_t)(struct _ref_t*, void*);
 
 #define _NONE_REF 1
 
+#ifndef _ref_count_t
 typedef unsigned _ref_count_t;
+#endif /* _ref_count_t */
 
 /* The reference structure should be always at the head of an object */
 typedef struct _ref_t {
diff --git a/core/my_basic.h b/core/my_basic.h
index a2402bc..19eee80 100755
--- a/core/my_basic.h
+++ b/core/my_basic.h
@@ -301,7 +301,7 @@ extern "C" {
 #endif /* mb_unrefvar */
 
 #ifndef mb_mem_tag_t
-	typedef unsigned short mb_mem_tag_t;
+typedef unsigned short mb_mem_tag_t;
 #endif /* mb_mem_tag_t */
 
 #ifndef mb_bytes_size