Android requires all libraries using abseil to have the source code local to the library's code. The
SHA hash below is the abseil-cpp hash that is in openscreen's DEPS file. The code is copied locally
in openscreen/third-party/abseil/src.

e19260fd7dbef881492fd73891e0be5bd4a09b95

How to update abseil local copy:

> git clone https://github.com/abseil/abseil-cpp.git src && cd src
> git checkout <hash>
> rm -rf .git .gitignore .github