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/testlib/ezbenchreport.c

@@ -26,17 +26,17 @@
 
 STATIC_YOINK("strnwidth");
 
-void __testlib_ezbenchreport(const char *form, uint64_t c1, uint64_t c2) {
-  uint64_t ns1, ns2;
+void __testlib_ezbenchreport(const char *form, double c1, double c2) {
+  long ns1, ns2;
   __warn_if_powersave();
-  ns1 = rintl(ConvertTicksToNanos(c1));
-  ns2 = rintl(ConvertTicksToNanos(c2));
+  ns1 = lrintl(ConvertTicksToNanos(c1));
+  ns2 = lrintl(ConvertTicksToNanos(c2));
   (fprintf)(stderr,
             VEIL("r", " *     %-19s l: %,9luc %,9luns   m: %,9luc %,9luns\n"),
-            form, c1, ns1, c2, ns2);
+            form, lrint(c1), ns1, lrint(c2), ns2);
 }
 
-void __testlib_ezbenchreport_n(const char *form, char z, size_t n, uint64_t c) {
+void __testlib_ezbenchreport_n(const char *form, char z, size_t n, double c) {
   char msg[128];
   uint64_t bps;
   long double cn, lat;