Introduces wrappers around memory allocation functions in `memory.h`
that should be used instead of the standard C ones.
These never return NULL and, with the exception of `mem_realloc()`,
zero-initialize the allocated memory like `calloc()` does.
All allocations made with the memory.h API must be deallocated with
`mem_free()`. Although standard `free()` will work on some platforms,
it's not portable (currently it won't work on Windows). Likewise,
`mem_free()` must not be used to free foreign allocations.
The standard C allocation functions are now diagnosed as deprecated.
They are, however, available with the `libc_` prefix in case interfacing
with foreign APIs is required. So far they are only used to implement
`memory.h`.
Perhaps the most important change is the introduction of the `ALLOC()`,
`ALLOC_ARRAY()`, and `ALLOC_FLEX()` macros. They take a type as a
parameter, and allocate enough memory with the correct alignment for
that type. That includes overaligned types as well. In most
circumstances you should prefer to use these macros. See the `memory.h`
header for some usage examples.
* Split replay.c into multiple files under replay/; improve logical
separation of replay-related code.
* Separate replay playback state from data.
* Get rid of global static replay struct and avoid unnecessary replay
copying.
* Replay playback and recording are now independent and may occur
simultaneously, although this functionality is not yet exposed. This
enables replay "re-recording" while synthesizing new desync check
events, possibly at a different rate from the original replay.
* Rate of recorded desync check events can now be controlled with the
TAISEI_REPLAY_DESYNC_CHECK_FREQUENCY environment variable. The default
value is 300 as before.
* Probably other stuff I forgot about.
