+AC_CXX_REQUIRE_STL
+
+# are covariant methods allowed?
+AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM([[]],
+ [[
+ class base { public: virtual base *GetPtr( void ) { return this; } };
+ class derived: virtual public base { public: virtual derived *GetPtr( void ) { return this; } };
+ ]])],
+ [AC_DEFINE([HAVE_COVARIANT_RETURNS],[1],[Define to 1 if C++ compiler supports covariant virtual methods.])])
+
+# is nullptr supported?
+AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM([[]],[[const char* ptr = nullptr;]])],
+ [AC_DEFINE([HAVE_NULLPTR],[1],[Define to 1 if C++ compiler supports nullptr keyword.])])