Hi,
I'm about to finish my work on libunwind [1] and I'd like to give you a brief overview on the different Android branches. The good news is that - if you don't need to unwind via DWARF debug frame information [2] - there are no additional patches required for Android. You can just pull the latest version from upstream [3], create an Android.mk and build it. This is what the "android" branch does [4]. The provided Android.mk re-uses the build system of libunwind and therefore relies on a few additional packages to be installed on the build system: autoconf libtool texlive-extra-utils. The Android.mk [5] uses autoreconf and libtool and will create three static libraries: libunwind.a libunwind-arm.a and libunwind-ptrace.a. The debuggerd of the linaro_android_2.3.5 branch requires a tiny patch [6] that adds the two libs to the LOCAL_STATIC_LIBRARIES.
In case you want/prefer a classic Android.mk that doesn't use the autotools you can use the "android-20111114" branch [7]. In addition to the Android.mk this one employs four header files that are normally generated by the configure script from the .in files [8]. The makefile creates static and a shared version of libunwind.
The third Android related libunwind branch is called "android-20111026" [9] and exists because a Linaro-Android manifest refers to a specific commit-id of this branch. Technically it's very similar to "android-20111114" but the history of the latter has been rebased.
So, basically there are two ways of building libunwind for Android. Choose whatever suits your needs best. Happy unwinding!
Regards Ken
[1] https://wiki.linaro.org/KenWerner/Sandbox/libunwind
[2] Unwinding via DWARF debug frames is nice to have but not a strict requirement on Android because most of the ELF file are stripped anyway and libunwind-ptrace can unwind the stack using the ARM specific unwind tables (-funwind-tables). Ping me if you still need the debug frame support - I've got a (hacky) patch for that on my hd.
[3] http://www.nongnu.org/libunwind/download.html
[4] git clone -b android git://git.linaro.org/people/kwerner/libunwind.git
[5] http://git.linaro.org/gitweb?p=people/kwerner/libunwind.git%3Ba=blob%3Bf=And...
[6] http://people.linaro.org/~kwerner/android/debuggerd/debuggerd-build.patch
[7] git clone -b android-20111114 git://git.linaro.org/people/kwerner/libunwind.git
[8] config.h, libunwind-common.h, libunwind.h and tdep/libunwind_i.h
[9] git clone -b android-20111026 git://git.linaro.org/people/kwerner/libunwind.git