As per my discussion with joduinn today (see https://bugzilla.mozilla.org/show_bug.cgi?id=769099#c12) I'd like to get access to a loaner buildbot machine to verify that the android NDK r8c can be installed and works to build our code.

kats: sorry, this didnt get handled same-day. jhopkins: thanks for grabbing this.

I got access to the loaner machine and verified that NDK r8c can be installed and used to build android (ARMv7) builds of fennec. I'm not sure if there's some official testing mechanism but I basically ran the commands that get run in a try build, except I skipped the parts that publish the builds, and manually installed r8c instead of r5c. I then created builds corresponding to the mozconfigs at: mobile/android/config/mozconfigs/android/nightly mobile/android/config/mozconfigs/android/debug mobile/android/config/mozconfigs/android-noion/nightly mobile/android/config/mozconfigs/android-armv6/nightly mobile/android/config/mozconfigs/android-armv6/debug updated as necessary to use the new NDK. I downloaded the builds and tried them out on a local device to do a sanity check on them. The ARMv7 ones (android/* and android-noion/*) all worked fine; the ARMv6 ones would crash with a SIGILL (I believe the same problem as bug 803601). This means that we currently cannot switch over ARMv6 builds to use NDK r8c, but we can still switch over the ARMv7 builds.