merge from dev-exp

include/mimalloc-internal.h

@@ -106,8 +106,11 @@ uintptr_t  _mi_heap_random(mi_heap_t* heap);
 
 // "stats.c"
 void       _mi_stats_done(mi_stats_t* stats);
-double     _mi_clock_end(double start);
-double     _mi_clock_start(void);
+
+typedef int64_t mi_msecs_t;
+mi_msecs_t  _mi_clock_now(void);
+mi_msecs_t  _mi_clock_end(mi_msecs_t start);
+mi_msecs_t  _mi_clock_start(void);
 
 // "alloc.c"
 void*       _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t size) mi_attr_noexcept;  // called from `_mi_malloc_generic`