Create a single backtrace library.

This library will be used to abstract away getting backtrace
data from how it is implemented. This is the first step to
replacing libcorkscrew with libunwind.

Bug: 8410085
Change-Id: Ie8f159e96a055d378e1ddc72d40239fba4cf52b7
Fix problems in libbacktrace.

- Add a wait for stop to backtrace_test. There is a possible race
  condition that is exposed when using libunwind.
- Fix a few calls to unwind function calls.

Bug: 8410085
Change-Id: I7487d687f6d4b7b05b8a96ad1c5f7183681e5c95
Only build host library on linux-x86.

Change-Id: I26d5bd4b34c3669897fea1488fa58972f4299757
Update debuggerd to use libbacktrace.

Remove all of the code in debuggerd that uses libcorkscrew directly
and replace with libbacktrace.

Also do a bit of refactoring to clean up some functions that were
passing around variables that weren't used.

Bug: 8410085

Change-Id: I27da4fbe3f12ce38a85b4432fc1119984c9c391b
Update comment from review.

Missed this typo that enh pointed out.

Bug: 8410085
Change-Id: Ic636ae218fc153bc5e3b1a0fdc2f7161980e5eec
Rewrite libbacktrace using C++.

The old code was essentially trying to be C++ in C and was awkward. This
change makes it all objects with a thin layer that C code can use.

There is a C++ backtrace object that is not very useful, this code will
replace it.

This change also includes moving the backtrace test to a gtest, and adding
coverage of all major functionality.

Bug: 8410085
Change-Id: Iae0f1b09b3dd60395f71ed66010c1ea5cdd37841
More libbacktrace fixes.

Included in minor fix ups is the addition of a warning macro to replace
all of the ALOGW calls.

Fix a race where multiple threads could be attempting to unwind the threads
of the current process at the same time.

Bug: 8410085

Change-Id: I02a65dc778dde690e5f95fc8ff069a32d0832fd1
Add corkscrew support for finding static symbols.

Change-Id: Ie557a9b0efadece75e1accaa7e214fb559eb19e1
Add some clarifying defines.

In order to be explicit in the Backtrace::Create() calls, adding a couple
of defines and some comments to describe what they mean.

Change-Id: I6ad08c529791821496a95fa33cea1c95b0a7eada
Use new defines in test code.

In addition, fix up the warnings and remove the -fpermissive when
compiling.

Change-Id: Ia27b902499b34ff3d881acb9057120af390baf2c
Enable libunwind on arm platforms.

Bug: 8410085
Change-Id: I8a645ec0e04b38fc186bbc0f0cc597e31b05cc55