diff --git a/ghc/lib/std/Makefile b/ghc/lib/std/Makefile
index d32470f0a98c35f180ff4b721f351bfe1624eb39..ed44f1c5fa2d0d419c67c8bfccf50a2876b5a5ab 100644
--- a/ghc/lib/std/Makefile
+++ b/ghc/lib/std/Makefile
@@ -55,6 +55,7 @@ Time_HC_OPTS        	 += -monly-3-regs
 # moment, but there you go..
 PrelNumExtra_HC_OPTS     += -H30m -K2m
 
+PrelPack_HC_OPTS	 += -K2m
 PrelBase_HC_OPTS         += -H10m
 PrelRead_HC_OPTS         += -H16m
 PrelTup_HC_OPTS          += -H12m