Don't enable GCC C++0x features in non-C++0x mode.

Update tests to actually fail unless we're in C++0x mode.
Fixes #5320.
Fixes #5319.

[SVN r70019]

test/boost_no_defaulted_functions.ipp

@@ -10,6 +10,10 @@
 //  TITLE:         C++0x defaulted functions unavailable
 //  DESCRIPTION:   The compiler does not support C++0x defaulted functions
 
+#if defined(__GNUC__) && !defined(__GXX_EXPERIMENTAL_CXX0X__)
+#  error Defaulted functions aren't really supported in non-C++0x mode
+#endif
+
 namespace boost_no_defaulted_functions {
 
   struct foo {

test/boost_no_deleted_functions.ipp

@@ -10,6 +10,10 @@
 //  TITLE:         C++0x =delete functions unavailable
 //  DESCRIPTION:   The compiler does not support C++0x =delete functions
 
+#if defined(__GNUC__) && !defined(__GXX_EXPERIMENTAL_CXX0X__)
+#  error Deleted functions aren't really supported in non-C++0x mode
+#endif
+
 namespace boost_no_deleted_functions {
 
   struct foo {

test/boost_no_explicit_cvt_ops.ipp

@@ -10,6 +10,10 @@
 //  TITLE:         C++0x explicit conversion operators unavailable
 //  DESCRIPTION:   The compiler does not support C++0x explicit conversion operators
 
+#if defined(__GNUC__) && !defined(__GXX_EXPERIMENTAL_CXX0X__)
+#  error This feature isn't really available in non-C++0x mode
+#endif
+
 namespace boost_no_explicit_conversion_operators {
 
   struct foo {

test/boost_no_lambdas.ipp

@@ -10,6 +10,10 @@
 //  TITLE:         C++0x lambda feature unavailable
 //  DESCRIPTION:   The compiler does not support the C++0x lambda feature
 
+#if defined(__GNUC__) && !defined(__GXX_EXPERIMENTAL_CXX0X__)
+#  error This feature isn't really available in non-C++0x mode
+#endif
+
 namespace boost_no_lambdas {
 
 int test()