Remove the link library to resolve linking/visibility concerns

[jeking3]

The link library can cause problems, for example:

#34
also the mailing list topic of "[boost] [all] Request for out of the box visibility support".

By removing the link library entirely this issue goes away. In my discussion with Jeff Garland, the original author:

If you look carefully at what is going on in the .cpp files it’s basically for standard string conversion support for things like months. So greg_month supports things like to_long_string() which need to take a ‘1’ and convert it into ‘January’. Anyway, there’s a few places in the library that this is used which would have to be replaced by a header compatible implementation.

For example see line 67 here.
https://github.com/boostorg/date_time/blob/develop/include/boost/date_time/date_parsing.hpp

Anyway, the c++98 compatible solutions can already be found in the library — you just need to make the statics part of a template — here’s one of the examples from the facet code — it’s a bit strange but it works. The facets have been header only since they came into the library.

https://github.com/boostorg/date_time/blob/develop/include/boost/date_time/date_names_put.hpp
//part of a template...
static const char_type default_special_value_names[3][17];
…

template<class Config, class charT, class OutputIterator>
const typename date_names_put<Config, charT, OutputIterator>::char_type
date_names_put<Config, charT, OutputIterator>::default_special_value_names[3][17] = {
{'n','o','t','-','a','-','d','a','t','e','-','t','i','m','e'},
{'-','i','n','f','i','n','i','t','y'},
{'+','i','n','f','i','n','i','t','y'} };

Anyway hope that helps

[JeffGarland]

I ended up doing this differently than I expected, but the work is completed for release 1.73 under issue #134.