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/cosmo2.c

@@ -24,11 +24,14 @@
 #include "libc/runtime/internal.h"
 #include "libc/runtime/memtrack.internal.h"
 #include "libc/runtime/runtime.h"
+#include "libc/runtime/stack.h"
 #include "libc/runtime/syslib.internal.h"
+#include "libc/sysv/consts/prot.h"
 #include "libc/thread/thread.h"
 #include "libc/thread/tls.h"
 #ifndef __x86_64__
 
+void __wipe(uintptr_t);
 int main(int, char **, char **) __attribute__((__weak__));
 
 typedef int init_f(int argc, char **argv, char **envp, unsigned long *auxv);
@@ -46,6 +49,9 @@ extern init_f *__preinit_array_start[] __attribute__((__weak__));
 extern init_f *__preinit_array_end[] __attribute__((__weak__));
 extern init_f *__init_array_start[] __attribute__((__weak__));
 extern init_f *__init_array_end[] __attribute__((__weak__));
+extern char ape_stack_vaddr[] __attribute__((__weak__));
+extern char ape_stack_memsz[] __attribute__((__weak__));
+extern char ape_stack_prot[] __attribute__((__weak__));
 extern pthread_mutex_t __mmi_lock_obj;
 extern int hostos asm("__hostos");
 
@@ -86,11 +92,21 @@ textstartup void cosmo(long *sp, struct Syslib *m1) {
   __oldstack = (intptr_t)sp;
   __pid = sys_getpid().ax;
 
-  // initialize mmap() manager extremely early
+  // initialize memory manager
   _mmi.n = ARRAYLEN(_mmi.s);
   _mmi.p = _mmi.s;
   __mmi_lock_obj._type = PTHREAD_MUTEX_RECURSIVE;
 
+  if (!IsTiny()) {
+    // record system-provided stack to memory manager
+    _mmi.i = 1;
+    _mmi.p->x = (uintptr_t)GetStackAddr() >> 16;
+    _mmi.p->y =
+        (uintptr_t)(GetStackAddr() + (GetStackSize() - FRAMESIZE)) >> 16;
+    _mmi.p->size = GetStackSize();
+    _mmi.p->prot = PROT_READ | PROT_WRITE;
+  }
+
 #if 0
 #if IsAsan()
   __asan_init(argc, argv, envp, auxv);
@@ -118,6 +134,7 @@ textstartup void cosmo(long *sp, struct Syslib *m1) {
   }
 
   // run program
+  if (!IsTiny()) __wipe(0);
   exit(main(argc, argv, envp));
 }