This replaces tests for __cplusplus >= 201103L, which are wrong with gcc 4.6 and earlier. Indeed these versions of gcc define __cplusplus = 1.
Reference:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=1773
As discussed on the list. We don't need it anymore, either we have a modern
compiler that supports C++11, or we fall back to boost. I kept and adjusted
the regex #define, since we cannot use std regex completely yet.
If we compile in C++11 mode, do not use the boost replacements for bind,
functional and shared_ptr. regex is excluded, since it misses match_partial, and
gcc does not provide a usable one in versions less than 4.9.0.
I also removed the #define for match_partial, since this is dangerous. Now you
get a compile error instead of subtle runtime differences.
