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

ape/ape.lds

@@ -416,7 +416,6 @@ SECTIONS {
 /*BEGIN: Post-Initialization Read-Only */
     . = ALIGN(__SIZEOF_POINTER__);
     KEEP(*(SORT_BY_NAME(.piro.relo.sort.*)))
-    PROVIDE_HIDDEN(__relo_end = .);
     . = ALIGN(__SIZEOF_POINTER__);
     KEEP(*(SORT_BY_NAME(.piro.data.sort.*)))
     KEEP(*(.piro.pad.data))
@@ -518,6 +517,7 @@ HIDDEN(_tdata_size = _tdata_end - _tdata_start);
 HIDDEN(_tbss_size = _tbss_end - _tbss_start);
 HIDDEN(_tbss_offset = _tbss_start - _tdata_start);
 HIDDEN(_tls_content = (_tdata_end - _tdata_start) + (_tbss_end - _tbss_start));
+HIDDEN(_tls_align = 1);
 
 HIDDEN(__privileged_addr = ROUNDDOWN(__privileged_start, PAGESIZE));
 HIDDEN(__privileged_size = (ROUNDUP(__privileged_end, PAGESIZE) -