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

test/libc/intrin/memmove_test.c

@@ -17,10 +17,10 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/macros.internal.h"
+#include "libc/mem/gc.internal.h"
 #include "libc/mem/mem.h"
 #include "libc/nexgen32e/nexgen32e.h"
 #include "libc/stdio/rand.h"
-#include "libc/mem/gc.internal.h"
 #include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
 #include "libc/testlib/ezbench.h"
@@ -83,7 +83,7 @@ TEST(memmove, bighug) {
 
 BENCH(memmove, bench) {
   volatile char *r;
-  int n, max = 8 * 1024 * 1024;
+  int n, max = 128 * 1024 * 1024;
   char *volatile p = gc(calloc(max, 1));
   char *volatile q = gc(calloc(max, 1));
   EZBENCH_N("memmove", 0, memmove(p, q, 0));