Remove next vars, since I don't think that somebody want to change it:
- bin
- lib
- include
And fix exports problem:
CMake Error: INSTALL(EXPORT "LibeventTargets") given absolute DESTINATION "/usr/lib/cmake/libevent" but the export references an installation of target "event_core_static" which has relative DESTINATION "lib".
Since they are useful for debugging, and if autotools build them then
cmamke has to do this too, to make migration more simple.
And now:
- tests: uses shared libraries (since this is upstreams one)
- other binaries: uses static libraries
This removes next private config:
- EVENT__NEED_DLLIMPORT
It did not work before correctly anyway, since cmake do not reset cache
entries by default, so that reset to "beta" didn't work.
But I don't think that making this variable cached is useful, so let's
remove this.
