Include exports in header files to support DLL creation on Windows about libnfc HOT 7 CLOSED

Thanks for report and solution.
r90 should fix this issue, code review wanted.

Regarding tools that use some bitutils.h functions, that's not a libbitutils but
libnfc :-), so theses tools should not use theses functions, or theses functions
should be macros.

Well, but they do. And they become part of libnfc at compile time of course. 
Attached 
patch fixes Windows building and adds the exports which are required by some 
tools. I 
wish they weren't needed :-)

Windows does not have usleep, but needs Sleep instead. 

And what about wanting to use C++ on Windows? This is not taken care of by your 
approach? 

I'm playing way too much with Windows! I don't even use it...

Hey Fkooman,
Patch have been applied in r92, r93 and r94. Thank you.

About wanting to use C++ on Windows, it seems that "__cplusplus" is also 
defined by
Windows C++ compilers (according to web search), so LIBNFC_EXPORT will put 
"extern
"C"" as expected. But maybe Windows C++ compiler needs specific code ?

My point was that what if you need both the DLL exports and the C++ extern "C" 
thingy. 

I don't pretend to understand how it works for C++, but it is needed in front 
of all
functions as well? So now you can either have DLL exports or C++ support...

Can you have a look at r97: considering your point, I had try to handle 
LIBNFC_EXPORT
define another way.

That seems nice! Although I have no way of testing this with C++ apps, maybe 
the dude
of Issue 16 can confirm this. Maybe reopen his issue until he confirms fixed.