Add a test for a recent POSIX change.

No code change required.

Bug: https://austingroupbugs.net/view.php?id=1647
Test: treehugger
Change-Id: I411a009bccafb4e2738f22199c64d8fe7dc105e3
diff --git a/tests/stdio_test.cpp b/tests/stdio_test.cpp
index 9cb0ffd..b3a296d 100644
--- a/tests/stdio_test.cpp
+++ b/tests/stdio_test.cpp
@@ -3685,4 +3685,11 @@
 #else
   GTEST_SKIP() << "no %w in glibc";
 #endif
-}
\ No newline at end of file
+}
+
+TEST(STDIO_TEST, printf_lc_0) {
+  // https://austingroupbugs.net/view.php?id=1647
+  char buf[BUFSIZ];
+  EXPECT_EQ(3, snprintf(buf, sizeof(buf), "<%lc>", L'\0'));
+  EXPECT_TRUE(!memcmp(buf, "<\0>", 3));
+}