+
+#----- testing rebuild on input change -----
+
+echo '# for-check 1' >>../src/for-test.sd.mk
+make -j4
+grep '^# for-check 1' src/Subdir.mk || false
+
+echo '# for-check 2' >>../lib/for-test.mk.in
+make -j4
+grep '^# for-check 2' lib/for-test.mk || false
+
+echo ok.