update/*/*: unified scanning of revisions/sources

update/blobs/download and update/project/repo both use
the same logic, for setting variables with awk and a
specially formatted configuration file.

unify this logic under include/option.sh, and use that.

Signed-off-by: Leah Rowe <leah@libreboot.org>

include/option.sh

@@ -1,4 +1,6 @@
-# SPDX-License-Identifier: MIT
+# SPDX-License-Identifier: GPL-3.0-only
+# SPDX-FileCopyrightText: 2022 Caleb La Grange <thonkpeasant@protonmail.com>
+# SPDX-FileCopyrightText: 2022 Ferass El Hafidi <vitali64pmemail@protonmail.com>
 # SPDX-FileCopyrightText: 2023 Leah Rowe <leah@libreboot.org>
 
 listitems()
@@ -16,3 +18,26 @@ listitems()
 	done
 	return ${rval}
 }
+
+scan_config()
+{
+	awkstr=" /\{.*${1}.*}{/ {flag=1;next} /\}/{flag=0} flag { print }"
+	confdir="${2}"
+	_fail="${3}"
+	revfile="$(mktemp -t sources.XXXXXXXXXX)" || \
+	    "${_fail}" "scan_config: Cannot initialise tmpfile"
+	cat "${confdir}/"* > "${revfile}" || \
+	    "${_fail}" "scan_config: Cannot concatenate files"
+	while read -r line ; do
+		set ${line} 1>/dev/null 2>/dev/null || :
+		if [ "${1%:}" = "depend" ]; then
+			depend="${depend} ${2}"
+		else
+			eval "${1%:}=\"${2}\""
+		fi
+	done << EOF
+	$(eval "awk '${awkstr}' \"${revfile}\"")
+EOF
+	rm -f "${revfile}" || \
+	    "${_fail}" "scan_config: Cannot remove tmpfile"
+}