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/mprotect-nt.greg.c

@@ -21,8 +21,6 @@
 #include "libc/runtime/internal.h"
 #include "libc/runtime/memtrack.internal.h"
 
-#define ADDR(x) ((char *)((int64_t)((uint64_t)(x) << 32) >> 16))
-
 textwindows int sys_mprotect_nt(void *addr, size_t size, int prot) {
   int rc = 0;
   unsigned i;
@@ -31,7 +29,7 @@ textwindows int sys_mprotect_nt(void *addr, size_t size, int prot) {
   __mmi_lock();
   p = addr;
   i = FindMemoryInterval(&_mmi, (intptr_t)p >> 16);
-  if (i == _mmi.i || (!i && p + size <= ADDR(_mmi.p[0].x))) {
+  if (i == _mmi.i || (!i && p + size <= (char *)ADDR_32_TO_48(_mmi.p[0].x))) {
     // memory isn't in memtrack
     // let's just trust the user then
     // it's probably part of the executable
@@ -42,7 +40,7 @@ textwindows int sys_mprotect_nt(void *addr, size_t size, int prot) {
     // memory is in memtrack, so use memtrack, to do dimensioning
     // we unfortunately must do something similar to this for cow
     for (; 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 <= p && p < y) || (x < p + size && p + size <= y) ||
           (p < x && y < p + size)) {