Android L regressions

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1. Conflict with libsigchain.so, which also intercepts sigaction.
2. Missing libcorkscrew.so. We need a different way to unwind from a signal 
handler.

Original issue reported on code.google.com by euge...@google.com on 23 Jul 2014 at 9:00

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https://code.google.com/p/android/issues/detail?id=74255

Original comment by euge...@google.com on 4 Sep 2014 at 8:42

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Status:
* current bionic master branch has a number of fixes to symbol resolution and 
signal unwinding. When that's released, we won't need libcorkscrew.so anymore.
* asan_device_setup sets allow_user_segv_handler=1 to allow libsigchain to take 
priority. Our segv handler becomes the first in line after libsigchain's, so 
everything works as before.
* asan_device_setup sets SELinux labels properly so that enforcing mode works 
fine.

Basically, everything works on master branch.

Original comment by euge...@google.com on 19 Sep 2014 at 3:10

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Original comment by infe...@chromium.org on 12 Oct 2014 at 4:25

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Can you attach the latest asan_device_setup.sh ? Mike can test it out and make 
sure stuff works on L correctly. Mike, you will see a copy of this in 
ClusterFuzz (with some changes). You would need to add the new changes in that 
file (you can't just replace it since it has some local changes needed for 
ClusterFuzz to work).

Original comment by infe...@chromium.org on 12 Oct 2014 at 4:28

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Up-to-date version of asan_device_setup can be found here:
http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/scripts/asan_devi
ce_setup?view=markup

Original comment by euge...@google.com on 12 Oct 2014 at 7:17