add bootloader configuration

create special entry with kernel command line to enable A11Y scripts.

configs/releng/efiboot/loader/entries/archiso-x86_64-speech-linux.conf

+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+title   Arch Linux install medium (x86_64, UEFI) with speach
+linux   /%INSTALL_DIR%/boot/x86_64/vmlinuz-linux
+initrd  /%INSTALL_DIR%/boot/intel-ucode.img
+initrd  /%INSTALL_DIR%/boot/amd-ucode.img
+initrd  /%INSTALL_DIR%/boot/x86_64/initramfs-linux.img
+options archisobasedir=%INSTALL_DIR% archisolabel=%ARCHISO_LABEL% speakup.synth=soft

configs/releng/syslinux/archiso_head.cfg

@@ -28,3 +28,4 @@ MENU COLOR msg07        37;40   #90ffffff #a0000000 std
 MENU COLOR tabmsg       31;40   #30ffffff #00000000 std
 
 MENU CLEAR
+MENU IMMEDIATE

configs/releng/syslinux/archiso_sys-linux.cfg

@@ -10,3 +10,14 @@ MENU LABEL Arch Linux install medium (x86_64, BIOS)
 LINUX boot/x86_64/vmlinuz-linux
 INITRD boot/intel-ucode.img,boot/amd-ucode.img,boot/x86_64/initramfs-linux.img
 APPEND archisobasedir=%INSTALL_DIR% archisolabel=%ARCHISO_LABEL%
+
+# accessability boot option
+LABEL arch64speatch
+TEXT HELP
+Boot the Arch Linux install medium on BIOS with speakup.
+It allows you to install Arch Linux or perform system maintenance with speatch feedback.
+ENDTEXT
+MENU LABEL Arch Linux install medium (x86_64, BIOS) with ^speatch
+LINUX boot/x86_64/vmlinuz-linux
+INITRD boot/intel-ucode.img,boot/amd-ucode.img,boot/x86_64/initramfs-linux.img
+APPEND archisobasedir=%INSTALL_DIR% archisolabel=%ARCHISO_LABEL% speakup.synth=soft