MSVC does not support SHARED and STATIC libraries with the same name,
so let's just build SHARED libraries by default instead (yes we can add
prefix but let's stick with this).
The reason for this is that in windows shared libraries requires .lib
file too, but this is not static library it is imported library for
shared (doh...), for more info [1] and [2].
[1]: https://docs.microsoft.com/en-us/windows/desktop/dlls/dynamic-link-library-creation
[2]: https://blogs.msdn.microsoft.com/oldnewthing/20091013-00/?p=16403
And when we build both static library can and will override shared
library imported part, let's take a look at event_extra.lib:
- before patch [3]:
$ less libevent-fail/lib/Debug/event_extra.lib | head
==> use library:contained_file to view a file in the archive
rw-rw-rw- 100666/100666 59568 Nov 21 23:55 2018 event_extra_static.dir/Debug/evrpc.obj
rw-rw-rw- 100666/100666 252219 Nov 21 23:55 2018 event_extra_static.dir/Debug/evdns.obj
rw-rw-rw- 100666/100666 203850 Nov 21 23:55 2018 event_extra_static.dir/Debug/http.obj
rw-rw-rw- 100666/100666 25907 Nov 21 23:55 2018 event_extra_static.dir/Debug/event_tagging.obj
[3]: https://ci.appveyor.com/project/azat/libevent/builds/20472024/job/t0o93v042jai0dj7
- "after patch" [4] (not after but the same effect):
$ less libevent-ok/lib/Debug/event_extra.lib | head
==> use library:contained_file to view a file in the archive
--------- 0/0 509 Nov 21 23:38 2018 event_extra.dll
...
[4]: https://ci.appveyor.com/project/azat/libevent/builds/20478998/job/ca9k3c76amc4qr76
Refs: #691
Long time ago in [1] cmake build was forced to compile both libraries
(SHARED and STATIC), since this is how our autotools build works.
[1]: 7182c2f561570cd9ceb704623ebe9ae3608c7b43 ("cmake: build SHARED and STATIC libraries (like autoconf does)")
And there is no way to configure this (and indeed you need to do this
for MSVC for example), so let's introduce option for this --
EVENT__LIBRARY_TYPE.
Plus now we have INTERFACE libraries, that we can use internally in
libevent's cmake rules to avoid strict to _shared/_static variant of the
libraries to link with samples/tests (we prefer SHARED over STATIC for
linking).
Also bump minimal cmake required version to 3.1 by the following
reasons:
- 3.1 is required for RPATH configuration under APPLE
- 3.0 is required for add_library(INTERFACE) (did not found it in 2.8.x
documentation)
- remove extra conditions
(anyway 3.1 was release 4 years ago, so I guess that most of the systems
will have it)
Because it is mauvais ton to use binaries instead of normal packages
(like apt-get in debian, pacman in arch, and others).
Plus that link was borken and according to [1] OpenSSL do not ship
binaries officially.
And personally I don't think that this is not obvious that you need
openssl libraries to build libevent with it's support, and BTW you need
headers too (of course).
[1]: https://www.openssl.org/community/binaries.htmlFixes: #562
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.
