- update to version 2.9.0
* Better check for objc runtime on Windows.
* Split linker flags to better support partial linking: 'ALL_LDFLAGS'
is now a combination of 'FINAL_LDFLAGS' and 'ALL_LDFLAGS'.
* Better support for newer gcc versions.
* Add support for storyboard files.
* Increase autoconf version to 2.65 and make autoconf handle
Objective-C++ and OBJCXX variables directly.
* Fix bug that prevented ARC from getting used.
* Link subproject object files directly instead of first merging them
into 'subproject.o'.
* Support building on Windows with Clang MSVC target.
* Improve mingw64 support: for instance, adopt the triplet used by
the mingw-w64 project rather than using the one returned by
autoconf. Fixes building Gorm.
- add keyring for source validation