build_iso.sh: Allow IPXE_TARGET to be passed as cli parameter

Refs. sysadm-environment#5250

configs/build_iso.sh

@@ -4,6 +4,10 @@ set -e
 
 BASEDIR=$(readlink -f "$(dirname "$0")/..")
 HOSTNAME=$1
+# Allow to define the intermediary IPXE_TARGET folder. This can pose problem
+# on old hardware (e.g. beaubourg generated iso would not boot on the default
+# path, we had to rename it to bin/ipxe.iso )
+IPXE_TARGET=${2-bin-x86_64-efi/ipxe.iso}
 
 CONFIG="${BASEDIR}/configs/${HOSTNAME}.yaml"
 IPXE_SCRIPT="${BASEDIR}/configs/${HOSTNAME}.ipxe"
@@ -19,7 +23,6 @@ j2 -f yaml "${BASEDIR}/configs/template.ipxe.j2" "${CONFIG}" >"${IPXE_SCRIPT}"
 # If not provided in the hostname configuration, fallback to the net0
 sed -i s'/{{IPXE_NET}}/net0/g' "${IPXE_SCRIPT}"
 
-IPXE_TARGET=bin-x86_64-efi/ipxe.iso
 
 make -C "${BASEDIR}/src" -j8 "${IPXE_TARGET}" EMBED="${IPXE_SCRIPT}" DEBUG=eth_slow NO_WERROR=1
 mv "${BASEDIR}/src/${IPXE_TARGET}" "${BASEDIR}/configs/${HOSTNAME}.iso"