--- a/src/runtime/Config.sparc-sunos
+++ b/src/runtime/Config.sparc-sunos
@@ -22,3 +22,7 @@
 OS_LIBS = -ldl -lsocket -lnsl -lrt
 
 GC_SRC = cheneygc.c
+
+# Nothing to do for after-grovel-headers.
+.PHONY: after-grovel-headers
+after-grovel-headers: