To define a plugin, you need to add the MYSQL_ADD_PLUGIN() macro into CMakeList.txt. Unlike in 5.1, there is no special plug.in script. If you need to perform system checks, use standard CMake techniques like CHECK_FUNCTION_EXISTS or CHECK_INCLUDE_FILE etc.

Note: There is NO autoheader-functionality. For example, CHECK_FUNCTION_EXISTS(epoll_wait HAVE_EPOLL_WAIT) will not automagically add "#define HAVE_EPOLL_WAIT 1" in config.h. Different plugins might chose different strategies to add plugin-specific defines

This is similar to what InnoDB does in 5.5. An example

CHECK_FUNCTION_EXISTS(epoll_wait HAVE_EPOLL_WAIT)
IF(HAVE_EPOLL_WAIT)
  ADD_DEFINITIONS(-DHAVE_EPOLL_WAIT=1)
ENDIF()

It is more work than in Strategy 1 but result is a cleaner solution:

1) You need to have plugin specific <plugin>_config.h.in with content similar to

 #cmakedefine HAVE_EPOLL_WAIT
#cmakedefine HAVE_EPOLL_CTL 

2) In CMakeLists.txt, add system checks

CHECK_FUNCTION_EXISTS(epoll_wait HAVE_EPOLL_WAIT)
CHECK_FUNCTION_EXISTS(epoll_ctl HAVE_EPOLL_CTL)

After all system checks, add

CONFIGURE_FILE(plugin_config.h.in plugin_config.h)

3) use #include "plugin_config.h" in your source files