ltdl support for versioned symbols

[Ludovic Courtès]

Hello!

I’m thinking about adding this to ltdl:

  void *lt_dlvsym (lt_dlhandle HANDLE, const char *NAME,
                   const char *VERSION);

On GNU systems[*], this would call ‘dlvsym’; on other systems, it would
call ‘lt_dlsym’.

Thoughts?

Thanks,
Ludo’.

[*] Solaris ld supports symbol versioning but seems to lack ‘dlvsym’.
    Are there other systems that support it?