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/log/showcrashreports.c

@@ -26,6 +26,7 @@
 #include "libc/log/log.h"
 #include "libc/macros.internal.h"
 #include "libc/mem/mem.h"
+#include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/stack.h"
 #include "libc/runtime/symbols.internal.h"
@@ -158,4 +159,6 @@ void ShowCrashReports(void) {
   InstallCrashHandler(SIGBUS, __got_sigbus, ef);    // misalign, mmap i/o failed
   InstallCrashHandler(SIGURG, __got_sigurg, ef);    // placeholder
   GetSymbolTable();
+  void __wipe(uintptr_t);
+  return __wipe(0);
 }