In the case of C++, I think that part of the problem is simply
the implementation difficulties when templates are involved.
Even with export, I think it would be very, very difficult to
implement the rules for C headers in C. (The C library is a
much simpler beast.) So while it's a sorry situation, I fear
that there's no good alternative.
It doesn't seem impossible (though I am likely missing something). How
about the following system:
For each header required by the standard, provide an internal version
(e.g. for <vector> provide <internal_vector>, or similar).
Each internal header should provide the interface required by the
standard with the following changes: all classes, class templates,
namespace functions and function templates, and namespace objects,
should have an internal name (e.g __internal_vector<> instead of vector<>).
Whenever a standard library header needs to include a standard header,
it should include the internal header instead, and use the internal names.
The "official" headers should map the required names to the internal
names. The mechanisms available include compiler specific methods,
inline forwarding functions, typedefs, references, and forwarding classes.
Is there anything in the standard which couldn't be implemented this way?