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/describeframe.c

@@ -26,12 +26,11 @@
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/winargs.internal.h"
 
-#define ADDR(x)     ((int64_t)((uint64_t)(x) << 32) >> 16)
 #define UNSHADOW(x) ((int64_t)(MAX(0, (x)-0x7fff8000)) << 3)
 #define FRAME(x)    ((int)((x) >> 16))
 
 forceinline pureconst bool IsBrkFrame(int x) {
-  unsigned char *p = (unsigned char *)((intptr_t)((uintptr_t)x << 32) >> 16);
+  unsigned char *p = (unsigned char *)ADDR_32_TO_48(x);
   return _weaken(__brk) && p >= _end && p < _weaken(__brk)->p;
 }
 
@@ -78,7 +77,8 @@ const char *(DescribeFrame)(char buf[32], int x) {
   char *p;
   if (IsShadowFrame(x)) {
     ksnprintf(buf, 32, "%s %s %.8x", GetFrameName(x),
-              GetFrameName(FRAME(UNSHADOW(ADDR(x)))), FRAME(UNSHADOW(ADDR(x))));
+              GetFrameName(FRAME(UNSHADOW(ADDR_32_TO_48(x)))),
+              FRAME(UNSHADOW(ADDR_32_TO_48(x))));
     return buf;
   } else {
     return GetFrameName(x);