diff --git a/mk/config.mk.in b/mk/config.mk.in
index b064f25b9259026f19bc12daefd61e13c6c2448f..8ddf3e2df430687e070e605aea4cf55c34a0446c 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -227,7 +227,7 @@ BuildingProfilingConcurrent=$(subst mr,YES,$(filter mr,$(WAYS)))
 # profiled prelude libraries.
 # When booting from .hc files, turn this off.
 ifeq "$(GhcWithHscBuiltViaC)" "YES"
-GhcLibWays
+GhcLibWays=
 else
 GhcLibWays=p
 endif