Add a regression test for diff -D

usr.bin/diff/tests/Makefile

@@ -21,7 +21,8 @@ ${PACKAGE}FILES+=	\
 	unified_c9999.out \
 	unified_9999.out \
 	header.out \
-	header_ns.out
+	header_ns.out \
+	ifdef.out
 
 NETBSD_ATF_TESTS_SH+=	netbsd_diff_test
 

usr.bin/diff/tests/diff_test.sh

@@ -4,6 +4,7 @@ atf_test_case simple
 atf_test_case unified
 atf_test_case header
 atf_test_case header_ns
+atf_test_case ifdef
 
 simple_body()
 {
@@ -70,10 +71,18 @@ header_ns_body()
 		diff -u empty hello
 }
 
+ifdef_body()
+{
+	atf_check -o file:$(atf_get_srcdir)/ifdef.out -s eq:1 \
+		diff -D PLOP "$(atf_get_srcdir)/input_c1.in" \
+		"$(atf_get_srcdir)/input_c2.in"
+}
+
 atf_init_test_cases()
 {
 	atf_add_test_case simple
 	atf_add_test_case unified
 	atf_add_test_case header
 	atf_add_test_case header_ns
+	atf_add_test_case ifdef
 }

usr.bin/diff/tests/ifdef.out

@@ -0,0 +1,26 @@
+/*
+ * A comment 
+ *
+#ifndef PLOP
+ * And another  bla
+#else /* PLOP */
+ * And another bla
+#endif /* PLOP */
+ *
+#ifndef PLOP
+ * And yet another
+#else /* PLOP */
+ * and yet another
+#endif /* PLOP */
+ */
+
+int
+main(void)
+{
+#ifdef PLOP
+
+#endif /* PLOP */
+	printf("something");
+
+	return (0);
+}