message: improve CircularBuffer error message
diff: @@ -105,7 +105,7 @@ void* CircularBuffer::alloc(size_t size) noexcept {
  data = mmap(nullptr, size * 2 + BLOCK_SIZE, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  ASSERT_POSTCONDITION(data,
  - "couldn't allocate %u KiB of memory for the command buffer",
  + "couldn't allocate %u KiB of virtual address space for the command buffer",
  (size * 2 / 1024));
  slog.d << "WARNING: Using soft CircularBuffer (" << (size * 2 / 1024) << " KiB)"
  