Haiku build fix post refactoring.

src/snmalloc/pal/pal_haiku.h

@@ -20,7 +20,7 @@ namespace snmalloc
      * PAL supports.
      *
      */
-    static constexpr uint64_t pal_features = PALPOSIX::pal_features;
+    static constexpr uint64_t pal_features = PALPOSIX::pal_features | Entropy;
 
     /**
      * Haiku requires an explicit no-reserve flag in `mmap` to guarantee lazy
@@ -37,6 +37,15 @@ namespace snmalloc
       SNMALLOC_ASSERT(is_aligned_block<page_size>(p, size));
       posix_madvise(p, size, POSIX_MADV_DONTNEED);
     }
+
+    /**
+     * Hopefully a temporary workaround until the kernel random feature
+     * is exposed properly in the userspace ?
+     */
+    static uint64_t get_entropy64()
+    {
+      return PALPOSIX::dev_urandom();
+    }
   };
 } // namespace snmalloc
 #endif