[Buildsystem] Provide C++11 feature support macros for backwards compatibility

config.h.cmake

@@ -26,6 +26,13 @@
 /* does the compiler support __attribute__((unused))? */
 #cmakedefine HAS_ATTRIBUTE_UNUSED 1
 
+/* old feature support macros which were tested until 2.3, keep around for one more release */
+/* As these are now always supported due to the new compiler requirements, they are directly */
+/* defined without an explicit test. */
+#define HAVE_VARIADIC_TEMPLATES  1
+#define HAVE_VARIADIC_CONSTRUCTOR_SFINAE 1
+#define HAVE_RVALUE_REFERENCES 1
+
 /* Define if you have a BLAS library. */
 #cmakedefine HAVE_BLAS 1
 

m4/cxx11_compiler.m4

@@ -63,4 +63,10 @@ AC_DEFUN([CXX11],[
       AC_MSG_WARN([Skipping test for C++11 support, make sure your compiler supports at least the feature set of GCC 4.4!])
     fi
   fi
+
+  # set feature support macros for backwards compatibility
+  AC_DEFINE(HAVE_VARIADIC_TEMPLATES, 1, [THIS MACRO IS DEPRECATED AND ONLY KEPT FOR BACKWARDS COMPATIBILITY UNTIL THE NEXT RELEASE!])
+  AC_DEFINE(HAVE_VARIADIC_CONSTRUCTOR_SFINAE, 1, [THIS MACRO IS DEPRECATED AND ONLY KEPT FOR BACKWARDS COMPATIBILITY UNTIL THE NEXT RELEASE!])
+  AC_DEFINE(HAVE_RVALUE_REFERENCES, 1, [THIS MACRO IS DEPRECATED AND ONLY KEPT FOR BACKWARDS COMPATIBILITY UNTIL THE NEXT RELEASE!])
+
 ])