This change adds several of the pieces needed to build Ceres on
Android. The port is incomplete, since GFlags doesn't build which
causes the tests to not build. However, simple_bundle_adjuster
builds and runs on the phone.
Thanks to Scott Ettinger for the original version of the minimal
GLog implementation which made this port possible. The Ceres logs
go to the various Android logging levels, as documented in
miniglog/glog/logging.h.
To control the Android build, this adds a new CMake build option:
-DBUILD_ANDROID=ON/OFF
However, users may not want to set this manually, and should
instead run the script found in android/build_android.sh. The
script calls the NDK to make a standalone toolchain, downloads the
android-cmake toolchain, then configures CMake to cross-compile
Ceres to Android.
Note: At time of writing, the android-cmake toolchain that the
script downloads from Google Code doesn't work with the latest
Jellybean NDK. It's possible to manually hack the toolchain file
to make it build by setting the compiler version and manually
setting the path to the STL includes. I don't yet have a patch
suitable for upstreaming to http://android-cmake.googlecode.com.
Change-Id: Icb615be203145e87413d6acd05883171a395499d
Sameer Agarwal