Cosmopolitan v3.5.5

This release perfects the new memory manager. The impact of the mmap()
rewrite (introduced by Cosmo v3.5.0) is that LLaMAfiler's tokenization
endpoint was previously handling 2 million requests per second and now
it's handling 3.3 million per second.

• 8c645fa Make mmap() scalable
• 3756870 Implement new red-black tree
• 1ff037d Add some mmap() documentation
• f7780de Make realloc() go 100x faster on Linux/NetBSD
• 76cea6c Squeeze more performance out of memory manager
• fdab49b Demonstrate signal safety of recursive mutexes
• 01587de Simplify memory manager

A few disruptive changes slipped in, but they're necessary. Aside from
the changes listed below, please note that you might need to update your
code to use sysconf(_SC_GRANSIZE) instead of sysconf(_SC_PAGESIZE)
when the alignment of the addr or offset parameters to mmap() is
the thing you care about.

• 1029dcc Reduce default stack size from 256kb to 81kb
• 86d884c Get rid of .internal.h convention in LIBC_INTRIN
• fc65422 Remove __mmap() and __munmap()

Other changes:

• 3f2a1b6 Fix greenbean example
• 0ed916a Fix a bug in example code
• 5a9a08d Fix regression in elf2pe program
• c697133 Fix typo in accept4-sysv.c (#1235)
• 15ea052 Reduce code size of mandatory runtime
• 6dbc3fb Add AMD cache sizes to o//tool/viz/cpuid
• bd6d9ff Get deathstar demo working again on metal
• 135d538 Make ctl::set use 30% less memory than libcxx