Reading an unbounded amount of data from a stream is a potential DoS vector. To manage this risk, readAllText() and readAllBytes() now accept a `limit` parameter. For source backwards-compatibility, this limit defaults to kj::maxValue.

Similar methods already exist on AsyncInputStream.

MinGW 7.2 (x86_64) build failed

Fixes a build error on GNU/Hurd.

Thanks to Bryan Boreham <bjboreham@gmail.com> for much help getting this started.

For portions currently copyright by Kenton (most of it), transfer copyright to Sandstorm Development Group, Inc. (Kenton's company).

The license change is practically meaningless, as MIT and BSD 2-clause are legally equivalent. However, the BSD 2-clause license is sometimes confused for its ugly siblings, BSD 3-clause and BSD 4-clause. The MIT license is more immediately recognizeable for what it is.

Rémy Blank and Jason Choy (the two non-trivial contributors) are on record as approving this change:

https://groups.google.com/d/msg/capnproto/xXDd2HUOCcc/gbe_COIuXKYJ

Apparently writev() imposes a limit on the vector size.  Work around that.  Not sure why libc doesn't already do this.

Switch to the new compiler.  All tests pass\!  Need to submit bootstrap copies of the generated code used by the compiler itself.  These bootstrap copies are still built by the old compiler at the moment.

Refactor compiler binary into a multi-tool with sub-commands like 'compile' and 'decode'.  The latter dynamically decodes binary input to text based on a provided schema file.

Implement mutex and once-init synchronization primitives.  Wrap pthreads for now, but plan on raw futexes later.

Mark every destructor "noexcept(false)" unless it is very clearly noexcept.  The change in C++11 making destructors default-noexcept was a mistake.

Add mechanism for catching exceptions that has limited use even with -fno-exceptions, as well as a mechanism to detect when a destructor is called during unwind and to avoid throwing in these situations.

Replace most CAPNPROTO_ASSERTs with the new logging/error macros.  Also add a SYSCALL macro and use it.  Also add commentary.