This will make things as std::to_string() and other C++ features
work with a modern and supported C++ library.
We package up libc++_shared.so and bump the revision of every C++
using package to make it rebuild against it.
Users who have built C++ using libraries or programs will probably
need to rebuild them if they are linked against Termux-supplied
libraries, as user code was previously linked against gnustl while
the system libraries are now using libc++, and it's not a good idea
to mix C++ standard libraries in a program.
For those using Docker build environments: run scripts/update-docker.sh
to pull the latest Docker image with r14 installed.
Otherwise, remove the $NDK directory (defaults to
$HOME/lib/android-ndk if not setup in the environment) and run
scripts/setup-android-sdk.sh to setup a r14 installation.
Let build-package.sh setup the $PREFIX/lib/libstdc++.so symlink
before building any package, to make sure that all C++ applications
link against a fully featured C++ standard library.
Avoid explicitly declaring a dependency on the libgnustl package
since everyone may link against it at will and instead mark it as
essential.
