diff --git a/objc/blocks_runtime.h b/objc/blocks_runtime.h
index 9f1545f..c20564e 100644
--- a/objc/blocks_runtime.h
+++ b/objc/blocks_runtime.h
@@ -2,35 +2,28 @@
 #pragma clang system_header
 #endif
 
+
 /*
  * Blocks Runtime
  */
 #include "Availability.h"
 #ifdef __cplusplus
-#include <stdbool.h>
+#define OBJC_BOOL_TYPE bool
+#define OBJC_BLOCK_PTR_TYPE void*
 #define BLOCKS_EXPORT extern "C"
 #else
+#define OBJC_BOOL_TYPE _Bool
+#define OBJC_BLOCK_PTR_TYPE id
 #define BLOCKS_EXPORT extern 
 #endif
 
 OBJC_PUBLIC BLOCKS_EXPORT void *_Block_copy(const void *);
 OBJC_PUBLIC BLOCKS_EXPORT void _Block_release(const void *);
 OBJC_PUBLIC BLOCKS_EXPORT const char *block_getType_np(const void *b) OBJC_NONPORTABLE;
-#ifdef __OBJC__
-#ifdef __cplusplus
-OBJC_PUBLIC BLOCKS_EXPORT bool _Block_has_signature(id);
-#else
-OBJC_PUBLIC BLOCKS_EXPORT _Bool _Block_has_signature(id);
-#endif
-OBJC_PUBLIC BLOCKS_EXPORT const char * _Block_signature(id);
-#else
-#ifdef __cplusplus
-OBJC_PUBLIC BLOCKS_EXPORT bool _Block_has_signature(void *);
-#else
-OBJC_PUBLIC BLOCKS_EXPORT _Bool _Block_has_signature(void *);
-#endif
-OBJC_PUBLIC BLOCKS_EXPORT const char * _Block_signature(void *);
-#endif
+
+OBJC_PUBLIC BLOCKS_EXPORT OBJC_BOOL_TYPE _Block_has_signature(OBJC_BLOCK_PTR_TYPE);
+OBJC_PUBLIC BLOCKS_EXPORT const char * _Block_signature(OBJC_BLOCK_PTR_TYPE);
+
 
 #define Block_copy(x) ((__typeof(x))_Block_copy((const void *)(x)))
 #define Block_release(x) _Block_release((const void *)(x))