add __BEGIN_DECLS / __END_DECLS

h_malloc.h

@@ -5,6 +5,8 @@
 
 #include <malloc.h>
 
+__BEGIN_DECLS
+
 #ifndef H_MALLOC_PREFIX
 #define h_malloc malloc
 #define h_calloc calloc
@@ -103,4 +105,6 @@ size_t h_malloc_object_size_fast(void *ptr);
 // passed size matches the allocated size.
 void h_free_sized(void *ptr, size_t expected_size);
 
+__END_DECLS
+
 #endif