Darwin: Fix dlmalloc warnings due to sizeof(size_t)
diff --git a/src/dlmalloc.c b/src/dlmalloc.c
index 2c55ceb..8725b4f 100644
--- a/src/dlmalloc.c
+++ b/src/dlmalloc.c
@@ -1661,7 +1661,7 @@ struct malloc_chunk {
typedef struct malloc_chunk mchunk;
typedef struct malloc_chunk* mchunkptr;
typedef struct malloc_chunk* sbinptr; /* The type of bins of chunks */
-typedef unsigned int bindex_t; /* Described below */
+typedef size_t bindex_t; /* Described below */
typedef unsigned int binmap_t; /* Described below */
typedef unsigned int flag_t; /* The type of various bit flag sets */