Initial hex2 tests pass on aarch64

lib/linux/aarch64-mes/elf64-body-exit-42.hex2

@@ -47,3 +47,4 @@ a8 0b 80 d2	# mov x8, #93
 :ELF_data
 65 78 69 74 34 32 20 64 61 74 61 20 68 65 72 65 # exit42 data here"
 00
+:#ELF_end

lib/linux/aarch64-mes/elf64-body-hello-mes.hex2

@@ -0,0 +1,69 @@
+### GNU Mes --- Maxwell Equations of Software
+### Copyright © 2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+###
+### This file is part of GNU Mes.
+###
+### GNU Mes is free software; you can redistribute it and/or modify it
+### under the terms of the GNU General Public License as published by
+### the Free Software Foundation; either version 3 of the License, or (at
+### your option) any later version.
+###
+### GNU Mes is distributed in the hope that it will be useful, but
+### WITHOUT ANY WARRANTY; without even the implied warranty of
+### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+### GNU General Public License for more details.
+###
+### You should have received a copy of the GNU General Public License
+### along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+
+### Commentary:
+
+# elf64-body-exit-42.hex2: `exit 42' for x86_64-linux written in hex2
+# assembly, for usage with generic elf64-header.hex2 and
+# elf64-footer-single-main.hex.
+
+# This ELF binary contains a symbol table, which means that objdump and
+# gdb can be used to inspect and debug.
+
+### Code:
+
+# @300
+:ELF_text
+:_start
+^~main 14	# b main
+
+00 00 00 00
+00 00 00 00
+00 00 00 00
+
+# @310
+:main
+	# print <hello>
+08 08 80 d2	# mov x8, #64
+20 00 80 d2	# mov x0, #1
+
+41 00 00 18	# ldr w1, .+8
+02 00 00 14	# b .+8
+&hello		# .word hello
+
+42 00 00 18	# ldr w2, .+8
+02 00 00 14	# b .+8
+%end>hello	# .word end-hello
+
+01 00 00 d4	# svc #0
+	
+	# exit 0
+a8 0b 80 d2	# mov x8, #93
+e0 03 1f aa	# mov x0, xzr
+01 00 00 d4	# svc #0
+7f 20 03 d5	# wfi
+
+00 00 00 00 00 00 00 00 # align to @350
+00 00 00 00
+# @350
+:ELF_data
+:hello
+48 65 6c 6c 6f 2c 20 47        # Hello, G
+4e 55 20 4d 65 73 21 0a        # NU Mes!\n
+:end
+:ELF_end