Andrey Semashev
Did you have a chance to test it with Boost locally? Or, if you have that knowledge, how compliant that implementation is? How many libraries other than Boost.Config and Boost.Container are going to be affected?
It is fairly standards-compliant, unless you consider extensions (as-is additional overloads to a standard function) to be non-conforming. The problem is that it sits on top of another standard library, and inherits some of its bugs, but not all of them. Therefore anything detecting a particular standard library and working around bugs needs to be more careful. So long as the boost library author is using boost config feature macros, there should be no problem, but if he's directly trying to detect which standard library is being used, for example directly assuming that this is libc++ because _LIBCPP_VERSION is defined, it might fail. There is a small issue related to conformance: it requires strict aliasing to be disabled (-fno-strict-aliasing). I know that's a bit controversial, but it shouldn't affect anything at the source level.