when checking the ABI with the C Preprocessor. Also, add the
new hearders to the cmake based ABI check.
cmake/abi_check.cmake:
Add headers which were added to the autotools ABI check.
Remove trailing spaces.
include/mysql/client_plugin.h:
Guard the inclusion of system headers.
connectors plugins
Implemented changes needed to keep the client plugin API compatible with
the existing plugins :
1. Provided an options() client plugin API to let the application pass
options to the plugin after loading it
2. Added "License" (const char *) to specify the client plugin's license
3. Added "mysql_api" as a placeholder that the client library can use
to pass function pointers to the plugin so that the plugin can call the
C lib back.
4. Updated the existing client plugins to comply with the API change.
5. Added more detailed error message generation for Windows.
