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/runtime/msync-nt.c

@@ -25,14 +25,12 @@
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/prot.h"
 
-#define ADDR(x) ((char *)((int64_t)((uint64_t)(x) << 32) >> 16))
-
 noasan textwindows int sys_msync_nt(char *addr, size_t size, int flags) {
   int i, rc = 0;
   char *a, *b, *x, *y;
   __mmi_lock();
   for (i = FindMemoryInterval(&_mmi, (intptr_t)addr >> 16); i < _mmi.i; ++i) {
-    x = ADDR(_mmi.p[i].x);
+    x = (char *)ADDR_32_TO_48(_mmi.p[i].x);
     y = x + _mmi.p[i].size;
     if ((x <= addr && addr < y) || (x < addr + size && addr + size <= y) ||
         (addr < x && y < addr + size)) {