[PATCH 2/2] libstdc++: Add a test for FTM redefinitions

[Arsen Arsenović via Gcc-patches]

This test detects redefinitions by compiling stdc++.h with
-Wsystem-headers.  Thanks Patrick Palka for the suggestion.

libstdc++-v3/ChangeLog:

        * testsuite/17_intro/versionconflict.cc: New test.
---
 libstdc++-v3/testsuite/17_intro/versionconflict.cc | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 libstdc++-v3/testsuite/17_intro/versionconflict.cc

diff --git a/libstdc++-v3/testsuite/17_intro/versionconflict.cc 
b/libstdc++-v3/testsuite/17_intro/versionconflict.cc
new file mode 100644
index 00000000000..4191c7a2b08
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/versionconflict.cc
@@ -0,0 +1,6 @@
+// { dg-do preprocess }
+// { dg-additional-options "-Wsystem-headers -Werror" }
+
+// Test for redefinitions of FTMs using bits/stdc++.h.
+#include <bits/stdc++.h>
+#include <version>
-- 
2.39.2