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/intrin/kprintf.greg.c

@@ -37,6 +37,7 @@
 #include "libc/intrin/weaken.h"
 #include "libc/limits.h"
 #include "libc/log/internal.h"
+#include "libc/log/libfatal.internal.h"
 #include "libc/macros.internal.h"
 #include "libc/nexgen32e/rdtsc.h"
 #include "libc/nexgen32e/uart.internal.h"
@@ -174,6 +175,7 @@ privileged static bool kismapped(int x) {
 
 privileged bool kisdangerous(const void *p) {
   int frame;
+  if (IsTiny()) return false;
   if (kisimagepointer(p)) return false;
   if (kiskernelpointer(p)) return false;
   if (IsOldStack(p)) return false;
@@ -189,7 +191,7 @@ privileged bool kisdangerous(const void *p) {
   return true;
 }
 
-privileged static void klog(const char *b, size_t n) {
+privileged dontinline void klog(const char *b, size_t n) {
 #ifdef __x86_64__
   int e;
   bool cf;