Fix build with memtest86+ 6.00

memtest86+ 6.00-1 (in testing as of this date) adds and changes its
available binaries:

  - /boot/memtest86+x32.bin
  - /boot/memtest86+x32.efi
  - /boot/memtest86+x64.bin
  - /boot/memtest86+x64.efi

Future live-build functionality would ideally incorporate these new
binaries (x64 for amd64 builds, efi for grub-efi), but in the meantime,
this is an MVP update which supports either old memtest86.bin or new
memtest86+x32.bin.

scripts/build/binary_memtest

@@ -56,13 +56,14 @@ then
 fi
 
 # Checking depends
+_MEMTEST_BIN="${LB_MEMTEST}"
 case "${LB_MEMTEST}" in
 	memtest86)
 		Check_package chroot /boot/memtest86.bin memtest86
 		;;
 
 	memtest86+)
-		Check_package chroot /boot/memtest86+.bin memtest86+
+		Check_package chroot /usr/share/doc/memtest86+/copyright memtest86+
 		;;
 esac
 
@@ -72,6 +73,19 @@ Restore_package_cache binary
 # Installing depends
 Install_packages
 
+case "${LB_MEMTEST}" in
+	memtest86+)
+		case "${LB_BUILD_WITH_CHROOT}" in
+			true)
+				[ -e "chroot/boot/${LB_MEMTEST}x32.bin" ] && _MEMTEST_BIN="${LB_MEMTEST}x32"
+				;;
+			false)
+				[ -e "/boot/${LB_MEMTEST}x32.bin" ] && _MEMTEST_BIN="${LB_MEMTEST}x32"
+				;;
+		esac
+		;;
+esac
+
 # Setting destination directory
 case "${LB_INITRAMFS}" in
 	live-boot)
@@ -89,11 +103,11 @@ mkdir -p "${DESTDIR}"
 # Installing memtest
 case "${LB_BUILD_WITH_CHROOT}" in
 	true)
-		cp -a chroot/boot/${LB_MEMTEST}.bin "${DESTDIR}"/memtest
+		cp -a "chroot/boot/${_MEMTEST_BIN}.bin" "${DESTDIR}"/memtest
 		;;
 
 	false)
-		cp -a /boot/${LB_MEMTEST}.bin "${DESTDIR}"/memtest
+		cp -a "/boot/${_MEMTEST_BIN}.bin" "${DESTDIR}"/memtest
 		;;
 esac