Changes imported from Abseil "staging" branch:

- 53419b5e123c4c9c47ecfe52ba747a271b03ae9c Add the sampling weight to MallocHook_SampledAlloc, so th... by Abseil Team <absl-team@google.com>
  - 8689c9a0dc685f50ba843a8d0d7d4274a1ec656a Factor out inline variable detection to separate macro. by Matt Calabrese <calabrese@google.com>
  - 0eac39ee9d81c03b8335c1cd3871d0dc4ec7bca7 Log the actual and expected durations for failed timing t... by Abseil Team <absl-team@google.com>

GitOrigin-RevId: 53419b5e123c4c9c47ecfe52ba747a271b03ae9c
Change-Id: I4ae8f5c0e924cdeee253fdf37d483d47893fc64c

absl/base/internal/malloc_hook_c.h

@@ -37,6 +37,7 @@ typedef struct {
   /* See malloc_hook.h  for documentation for this struct. */
   MallocHook_AllocHandle handle;
   size_t allocated_size;
+  double weight;
   int stack_depth;
   const void* stack;
 } MallocHook_SampledAlloc;