diff --git a/include/boost/config/stdlib/libstdcpp3.hpp b/include/boost/config/stdlib/libstdcpp3.hpp
index 205489a9..14dca142 100644
--- a/include/boost/config/stdlib/libstdcpp3.hpp
+++ b/include/boost/config/stdlib/libstdcpp3.hpp
@@ -143,6 +143,12 @@
 #  define BOOST_LIBSTDCXX_VERSION 40300
 #endif
 
+#if (BOOST_LIBSTDCXX_VERSION < 50100)
+// libstdc++ does not define this function as it's deprecated in C++11, but clang still looks for it,
+// defining it here is a terrible cludge, but should get things working:
+extern "C" char *gets (char *__s);
+#endif
+
 //
 //  GCC 4.8 and 9 add working versions of <atomic> and <regex> respectively.
 //  However, we have no test for these as the headers were present but broken
diff --git a/test/boost_has_nl_types_h.ipp b/test/boost_has_nl_types_h.ipp
index 9126adbf..e23f0a21 100644
--- a/test/boost_has_nl_types_h.ipp
+++ b/test/boost_has_nl_types_h.ipp
@@ -17,7 +17,7 @@ namespace boost_has_nl_types_h{
 int test()
 {
    nl_catd cat = catopen("foo", 0);
-   if(cat >= 0) catclose(cat);
+   if(cat != (nl_catd)-1) catclose(cat);
    return 0;
 }