diff --git a/lib/system/cellsets.nim b/lib/system/cellsets.nim
index 07bf440753..249dd522cf 100644
--- a/lib/system/cellsets.nim
+++ b/lib/system/cellsets.nim
@@ -61,7 +61,7 @@ else:
         line: int
       elif useCellIds:
         id: int
-      elif defined(cpu32):
+      elif sizeof(int) == 4:  # 32-bit only
         headerAlignPad: array[8, byte]  # so addr(data) ≡ 8 (mod 16)
 
     PCell = ptr Cell