diff --git a/mk/config.mk.in b/mk/config.mk.in
index ea87badadd45604aa82eb2c19376d2fbb0f18e2e..bdc4faea891c6a707d7d8daabacc7510aa512a67 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -249,7 +249,12 @@ else
 ifeq "$(strip $(way))" "mr"
 GhcLibHcOpts= -O
 else
+ifeq "$(GhcWithHscBuiltViaC)" "NO"
 GhcLibHcOpts= -O -split-objs -odir $*
+else
+#NB: .hc files need to distributed in *unsplit* form.
+GhcLibHcOpts= -O
+endif
 endif
 endif