Add new build-time configuration feature.

test/Jamfile.v2

@@ -15,6 +15,7 @@ project
 
 
 import modules ;
+import ../checks/config : requires ;
 
 local is_unix = [ modules.peek : UNIX ] ;
 
@@ -69,6 +70,7 @@ test-suite config
     [ run cstdint_test.cpp : : : <warnings>all <toolset>gcc:<cxxflags>"-Wno-long-long -Wextra" <toolset>darwin:<cxxflags>-Wno-long-long ]
     [ run cstdint_test2.cpp : : : <warnings>all <toolset>gcc:<cxxflags>"-Wno-long-long -Wextra" <toolset>darwin:<cxxflags>-Wno-long-long ]
     [ compile cstdint_include_test.cpp : <warnings>all <toolset>gcc:<cxxflags>-Wextra ]
+    [ run config_build_check.cpp : : : [ requires int128 cxx11_constexpr cxx11_user_defined_literals ] ]
   ;
 
 obj has_clang_implicit_fallthrough : cmd_line_check.cpp :

test/all/Jamfile.v2

@@ -1,7 +1,7 @@
 #
 # Regression test Jamfile for boost configuration setup.
 # *** DO NOT EDIT THIS FILE BY HAND ***
-# This file was automatically generated on Wed May 28 17:13:04 2014
+# This file was automatically generated on Thu Jun 05 18:54:37 2014
 #  by libs/config/tools/generate.cpp
 # Copyright John Maddock.
 # Use, modification and distribution are subject to the 

test/config_build_check.cpp

@@ -0,0 +1,18 @@
+//  Copyright John Maddock 2014.
+//  Use, modification and distribution are subject to the 
+//  Boost Software License, Version 1.0. (See accompanying file 
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+//  See http://www.boost.org/libs/config for the most recent version.//
+//  Revision $Id$
+//
+
+#  include "../test/boost_has_int128.ipp"
+#  include "../test/boost_no_constexpr.ipp"
+#  include "../test/boost_no_cxx11_user_lit.ipp"
+
+int main( int, char *[] )
+{
+   return boost_has_int128::test() || boost_no_cxx11_constexpr::test() || boost_no_cxx11_user_defined_literals::test();
+}
+

test/config_info.cpp

@@ -1119,6 +1119,13 @@ void print_boost_macros()
 
 
 
+
+
+
+
+
+
+
    // END GENERATED BLOCK
 
    PRINT_MACRO(BOOST_INTEL);

test/config_test.cpp

@@ -1,4 +1,4 @@
-//  This file was automatically generated on Wed May 28 17:13:04 2014
+//  This file was automatically generated on Thu Jun 05 18:54:37 2014
 //  by libs/config/tools/generate.cpp
 //  Copyright John Maddock 2002-4.
 //  Use, modification and distribution are subject to the