add optional pv tool

use pv to give feedback on copying the airootfs to RAM when copytoram
kernel parameter is given

archiso/initcpio/hooks/archiso

@@ -69,10 +69,23 @@ _mnt_sfs() {
     # defined via initcpio's parse_cmdline()
     if [ "${copytoram}" = "y" ]; then
         msg -n ":: Copying squashfs image to RAM..."
-        if ! cp -- "${img}" "/run/archiso/copytoram/${img_fullname}" ; then
+
+        # in case we have pv use it to display copy progress feedback otherwise
+        # fallback to using plain cp
+        if [ -x /usr/bin/pv ]; then
+            echo ""
+            (pv "${img}" > "/run/archiso/copytoram/${img_fullname}")
+            local rc=$?
+        else
+            (cp -- "${img}" "/run/archiso/copytoram/${img_fullname}")
+            local rc=$?
+        fi
+
+        if [ $rc != 0 ]; then
             echo "ERROR: while copy '${img}' to '/run/archiso/copytoram/${img_fullname}'"
             launch_interactive_shell
         fi
+
         img="/run/archiso/copytoram/${img_fullname}"
         msg "done."
     fi

archiso/initcpio/install/archiso

@@ -18,6 +18,7 @@ build() {
     add_binary truncate
     add_binary gpg
     add_binary grep
+    add_binary pv
 
     add_file /usr/lib/udev/rules.d/60-cdrom_id.rules
     add_file /usr/lib/udev/rules.d/10-dm.rules

configs/baseline/efiboot/loader/entries/archiso-x86_64-linux-ram.conf

+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+title   Arch Linux (x86_64, UEFI) Copy to RAM
+linux   /%INSTALL_DIR%/boot/x86_64/vmlinuz-linux
+initrd  /%INSTALL_DIR%/boot/x86_64/initramfs-linux.img
+options archisobasedir=%INSTALL_DIR% archisolabel=%ARCHISO_LABEL% copytoram

configs/baseline/packages.x86_64

@@ -6,6 +6,7 @@ linux
 mkinitcpio
 mkinitcpio-archiso
 openssh
+pv
 qemu-guest-agent
 syslinux
 virtualbox-guest-utils-nox

configs/baseline/syslinux/syslinux-linux.cfg

@@ -6,3 +6,9 @@ MENU LABEL Arch Linux (x86_64, BIOS)
 LINUX /%INSTALL_DIR%/boot/%ARCH%/vmlinuz-linux
 INITRD /%INSTALL_DIR%/boot/%ARCH%/initramfs-linux.img
 APPEND archisobasedir=%INSTALL_DIR% archisolabel=%ARCHISO_LABEL%
+
+LABEL arch-ram
+MENU LABEL Arch Linux (x86_64, BIOS) Copy to RAM
+LINUX /%INSTALL_DIR%/boot/%ARCH%/vmlinuz-linux
+INITRD /%INSTALL_DIR%/boot/%ARCH%/initramfs-linux.img
+APPEND archisobasedir=%INSTALL_DIR% archisolabel=%ARCHISO_LABEL% copytoram