Make considerably more progress on AARCH64

- Utilities like pledge.com now build
- kprintf() will no longer balk at 48-bit addresses
- There's a new aarch64-dbg build mode that should work
- gc() and defer() are mostly pacified; avoid using them on aarch64
- THIRD_PART_STB now has Arm Neon intrinsics for fast image handling

libc/intrin/kpollnames.S

@@ -0,0 +1,46 @@
+/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
+│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/fmt/magnumstrs.internal.h"
+#include "libc/macros.internal.h"
+
+	.macro	.e e s
+	.long	\e - kPollNames
+	.long	.L\@ - kPollNames
+	.rodata.str1.1
+.L\@:	.string	"\s"
+	.previous
+	.endm
+
+	.section .rodata,"a",@progbits
+	.balign	4
+	.underrun
+kPollNames:
+        .e	POLLNVAL	"POLLNVAL"
+	.e	POLLWRNORM	"POLLWRNORM"
+	.e	POLLWRBAND	"POLLWRBAND"
+	.e	POLLRDNORM	"POLLRDNORM"
+	.e	POLLRDHUP	"POLLRDHUP"
+	.e	POLLRDBAND	"POLLRDBAND"
+	.e	POLLHUP		"POLLHUP"
+	.e	POLLERR		"POLLERR"
+	.e	POLLPRI		"POLLPRI"
+	.e	POLLOUT		"POLLOUT"
+	.e	POLLIN		"POLLIN"
+	.endobj	kPollNames,globl,hidden
+	.overrun