The cosmopolitan command interpreter now has 13 builtin commands,
variable support, support for ; / && / || syntax, asynchronous support,
and plenty of unit tests with bug fixes.
This change fixes a bug in posix_spawn() with null envp arg. strace
logging now uses atomic writes for scatter functions. Breaking change
renaming GetCpuCount() to _getcpucount(). TurfWar is now updated to use
the new token bucket algorithm. WIN32 affinity masks now inherit across
fork() and execve().
