Better support for msys2.

Creates cpu_iphone.c and has it selected for iOS instead of cpu_posix.c

Various Windows fixes.

Adding MSVC's grpc++ project file.

Make metadata_test test_things_stick_around use fewer strings

clang-format c++ code

Dodging VisualStudio's #define of max().

-) using dupenv_s instead of getenv_s and calling strdup ourselves.
-) few impossible-to-obtain if checks.
-) various signed/unsigned casting.
-) using time_t instead of time32_t
-) checking output of FormatMessage for failures.
-) don't redefine _WIN32_WINNT without undefining it first.
-) fixed msvc's interlocked casting.
-) renamed AddPort to AddListeningPort.
-) added protobuf's third_party includes to search path.
-) added a missing definition for inet_ntop in mingw32.
-) removed useless declarations.

Add jwt_token_creds test case to interop test for c++

Print out status when it is not ok in interop tests

Node differentiate between binary and string headers

Fixes for Windows atomics.

Adds a dockerfile and script for building a tar archive containing protoc and the plugins

- the name includes a version
- the top-level directory of the tar has the same name as the archive

This test is quadratic in nstr and times out under tsan.

-) gpr_atm_no_barrier_load should actually return something.
-) If compiling under mingw32, your compiler is gcc and gcc atomics become available.

Adds back calls to #finish at the end of server calls

Exposes the metadata method in server-side ActiveCall view classes

Add csharp server

wrap refresh token credentials in c++

Fixes reference to variable in the auth package

Unconditionally add a newline if a test times out or fails.

Failure should generally result in output unless something goes wrong,
but timeout currently doesn't, but should be printed 100% of the time.

Factor out interface-specific early_adopter code

Refactors early_adopter such that interface-specific code is located in
the framework module as a submodule `alpha`.