fix building on bash even tho I don't use bash lol

build.sh

@@ -73,8 +73,8 @@ include() {
 set_md_metadata() {
 	eval ' {
 		# if 1st line isnt all -, skip setting metadata
-		IFS= read -r _
-		case "$_" in
+		IFS= read -r __first
+		case "$__first" in
 			*[!-]*) return ;;
 		esac