Make improvements

This change progresses our AARCH64 support:

- The AARCH64 build and tests are now passing
- Add 128-bit floating-point support to printf()
- Fix clone() so it initializes cosmo's x28 TLS register
- Fix TLS memory layout issue with aarch64 _Alignas vars
- Revamp microbenchmarking tools so they work on aarch64
- Make some subtle improvements to aarch64 crash reporting
- Make kisdangerous() memory checks more accurate on aarch64
- Remove sys_open() since it's not available on Linux AARCH64

This change makes general improvements to Cosmo and Redbean:

- Introduce GetHostIsa() function in Redbean
- You can now feature check using pledge(0, 0)
- You can now feature check using unveil("",0)
- Refactor some more x86-specific asm comments
- Refactor and write docs for some libm functions
- Make the mmap() API behave more similar to Linux
- Fix WIFSIGNALED() which wrongly returned true for zero
- Rename some obscure cosmo keywords from noFOO to dontFOO

libc/sysv/syscalls.sh

@@ -36,7 +36,6 @@ dir=libc/sysv/calls
 scall	sys_exit		0x00100100120010e7	0x05e	globl hidden # a.k.a. exit_group
 scall	sys_read		0x8038038032803800	0x03f	globl hidden
 scall	sys_write		0x8048048042804801	0x040	globl hidden
-scall	sys_open		0x8058058052805802	0x0b4	globl hidden
 scall	sys_close		0x0060060062006003	0x039	globl hidden
 scall	__sys_stat		0x1b7026fff2152004	0x04f	globl hidden # FreeBSD 11→12 fumble; use sys_fstatat(); blocked on Android
 scall	__sys_fstat		0x1b80352272153005	0x050	globl hidden # needs __stat2linux()
@@ -363,7 +362,7 @@ scall	sys_io_uring_register	0xfffffffffffff1ab	0x1ab	globl
 #────────────────────────RHEL CLOUD────────────────────────────────── # ←──────┬─ red hat terminates community release of enterprise linux circa 2020
 scall	sys_pledge		0xfff06cffffffffff	0xfff	globl hidden # └─ online linux services ban the president of united states of america
 scall	sys_msyscall		0xfff025ffffffffff	0xfff	globl # no wrapper
-scall	sys_bogus		0x00b5005002500500	0xfff	globl
+scall	sys_bogus		0x00b5005002500500	0x500	globl
 scall	sys_open_tree		0xfffffffffffff1ac	0x1ac	globl # no wrapper
 scall	sys_move_mount		0xfffffffffffff1ad	0x1ad	globl # no wrapper
 scall	sys_fsopen		0xfffffffffffff1ae	0x1ae	globl # no wrapper